Well, some observations as to why these trends happen...
NES age: Platformers. Platformers everywhere.: It was also because of the tech. You couldn't produce a 3D game and it was either top-down or sidescroller basically. It's not like today where you can make a diverse 3D plane, you were stuck in two dimensions, which often meant platformers for anything that wasn't a RPG or top-down shooter.
SNES age: Mascots were the largest thing here, and Platforming still going strong, but the rise of RPGs starts in this age.: Mainly due to a crossroads between Sega and Nintendo on their competition. Mario also started branching out here with Super Mario Kart, SMRPG, etc.
PS1 age: You got TONS of RPGs flooding the market here, on all platforms. Platformers are on the way out the door. A few FPS games are released during this age.: RPGs became popular due to the rise of cinematics. the PSX, with its larger storage space, allowed for more pre-rendered cutscenes, adding much more cinematic storytelling. Also FFVII was a huge success for a want for more RPGs came.
PS2 age: Still tons of RPGs on the PS2, some on the GC, but FPS starts the slow creep to the top on the Xbox. Platformers still cling to life on the Gamecube: Funny how platformers "cling to life" on the Gamecube when there was like two major platformer franchises on the PS2 (Jak and Daxter/Ratchet and Clank) not to mention a few oddball platformers here and there (pretty sure Psychonauts counts although I never played it, plus Wrath of Cortex is still a great Crash game). FPS games start to immerge because of their competitive nature and online gaming presents an avenue for this to be a centerpoint.
360/PS3 age: FPS all day err day. WRPGs are still going strong, but JRPGs are showing the signs of death. Platformers are officially dead except for Wii and handhelds.: FPS games flourished because online tech really came to fruition. Every console had it, even the PSP and DS. But now you could fit more people in a game, have digital distribution services to continuing adding content to the games, and use voice chat and parties to make communication better than ever. Also, platformers are certainly not dead if you played Rayman Origins. Platformers really begin to live on in handhelds and XBLA/PSN/WiIWare games. Just look at the number of DS platformers and you'll be flabergasted. It's certainly not a bad thing, it's just an evolution of the genre. Also the JRPG trend basically died out because WRPGs began getting better and more plentiful. Even on the last generation you saw Morrowind, KOTOR, and Jade Empire for some major ones. But these were completely blown away by Oblviion, Skyrim, Mass Effect (as a series), and Dragon Age (well, DA: O, we don't talk about DA2).
These "trends" happen for a reason and at this time, there's nothing to suggest that the FPS genre would die. And I really don't want it to. There's more amazing FPS games this generation than bad. If you don't think the FPS can live, go play a Valve game. They've used the same engine for basically what, 8 years now, but continually make largely innovative and excellent games. From Half Life 2 to Portal 2, they're advancing the frontier while using, by today's standards, and old and outdated engine.
People only dislike the FPS genre because it's popular. Look at Halo. Hate this statement as much as you want, but it's true: it's more like the old FPS games of yesteryear than any CoD can or will be. You can still jump in it, use tons of fantastical weapons (from your pistols, battle rifles, rocket launchers, and essentially a goddamn laser cannon), and hell, you still get goddamn shields and vehicles to fuck around in. I played Halo and Halo 2 a bit but couldn't really enjoy Halo 3, but from what I played of Halo Reach, I thought it was rather fun.
Then there's your Borderlands, an excellent FPRPG (according to the box), Perfect Dark XBLA (possibly the best reissuing of a game ever), Cell Factor: The PK Wars (little known but very fun), and every Valve game (Portal/2, Half Life 2, TF2, Counterstrike Source, L4D/2, etc).
No one would be viewing the FPS genre as a wart on the gooch of gaming if it wasn't for the popularity of Call of Duty and Halo. It's absolutely true.
NES age: Platformers. Platformers everywhere.: It was also because of the tech. You couldn't produce a 3D game and it was either top-down or sidescroller basically. It's not like today where you can make a diverse 3D plane, you were stuck in two dimensions, which often meant platformers for anything that wasn't a RPG or top-down shooter.
SNES age: Mascots were the largest thing here, and Platforming still going strong, but the rise of RPGs starts in this age.: Mainly due to a crossroads between Sega and Nintendo on their competition. Mario also started branching out here with Super Mario Kart, SMRPG, etc.
PS1 age: You got TONS of RPGs flooding the market here, on all platforms. Platformers are on the way out the door. A few FPS games are released during this age.: RPGs became popular due to the rise of cinematics. the PSX, with its larger storage space, allowed for more pre-rendered cutscenes, adding much more cinematic storytelling. Also FFVII was a huge success for a want for more RPGs came.
PS2 age: Still tons of RPGs on the PS2, some on the GC, but FPS starts the slow creep to the top on the Xbox. Platformers still cling to life on the Gamecube: Funny how platformers "cling to life" on the Gamecube when there was like two major platformer franchises on the PS2 (Jak and Daxter/Ratchet and Clank) not to mention a few oddball platformers here and there (pretty sure Psychonauts counts although I never played it, plus Wrath of Cortex is still a great Crash game). FPS games start to immerge because of their competitive nature and online gaming presents an avenue for this to be a centerpoint.
360/PS3 age: FPS all day err day. WRPGs are still going strong, but JRPGs are showing the signs of death. Platformers are officially dead except for Wii and handhelds.: FPS games flourished because online tech really came to fruition. Every console had it, even the PSP and DS. But now you could fit more people in a game, have digital distribution services to continuing adding content to the games, and use voice chat and parties to make communication better than ever. Also, platformers are certainly not dead if you played Rayman Origins. Platformers really begin to live on in handhelds and XBLA/PSN/WiIWare games. Just look at the number of DS platformers and you'll be flabergasted. It's certainly not a bad thing, it's just an evolution of the genre. Also the JRPG trend basically died out because WRPGs began getting better and more plentiful. Even on the last generation you saw Morrowind, KOTOR, and Jade Empire for some major ones. But these were completely blown away by Oblviion, Skyrim, Mass Effect (as a series), and Dragon Age (well, DA: O, we don't talk about DA2).
These "trends" happen for a reason and at this time, there's nothing to suggest that the FPS genre would die. And I really don't want it to. There's more amazing FPS games this generation than bad. If you don't think the FPS can live, go play a Valve game. They've used the same engine for basically what, 8 years now, but continually make largely innovative and excellent games. From Half Life 2 to Portal 2, they're advancing the frontier while using, by today's standards, and old and outdated engine.
People only dislike the FPS genre because it's popular. Look at Halo. Hate this statement as much as you want, but it's true: it's more like the old FPS games of yesteryear than any CoD can or will be. You can still jump in it, use tons of fantastical weapons (from your pistols, battle rifles, rocket launchers, and essentially a goddamn laser cannon), and hell, you still get goddamn shields and vehicles to fuck around in. I played Halo and Halo 2 a bit but couldn't really enjoy Halo 3, but from what I played of Halo Reach, I thought it was rather fun.
Then there's your Borderlands, an excellent FPRPG (according to the box), Perfect Dark XBLA (possibly the best reissuing of a game ever), Cell Factor: The PK Wars (little known but very fun), and every Valve game (Portal/2, Half Life 2, TF2, Counterstrike Source, L4D/2, etc).
No one would be viewing the FPS genre as a wart on the gooch of gaming if it wasn't for the popularity of Call of Duty and Halo. It's absolutely true.
. Saves on time, soap, water and money having to wash them. 
