If the quality of the 3DS library is lower than the DS's library, it's the developer's fault. At least with Nintendo they have been doing a pretty good job with games in the 3DS most of the time. It's okay you don't care about first parties in 3DS, but they are part of the 3DS library whether you like it or not .On the 3ds I still hold it is not doing anywhere near DS quality in terms of games (we are now over 3 years in -- http://gbatemp.net/threads/5-years-of-ds-roms-in-5-days-year-3.236882/), that said most of the devs I like have mostly going andrIOS and I did not care for most first party/captive dev offerings.
That said I have never found a console that repeated the snes or ps1 quality of library for example. Most people will disagree with me, but the ps2/ps3/gamecube/wii/xbox/xbox360 are nowhere near the quality of snes/ps1. Nevertheless they are not bad consoles at all, it's just that when you have such a great library in one generation it will be pretty hard to repeat the triumph anytime soon.
With the DS I believe it's this case, it had a really awesome library... It will take a while before this quality repeat itself in handhelds