Those are all very different situations. The PS3 was extremely expensive because it was using the newest technology. Blu-ray players were expensive as hell when the PS3 released, and it has one built in. On top of the other price upping bits of the PS3, and the need to profit, the price got a bit out of hand. In recent years, prices have dropped pretty drastically on the technology used in the PS3. The price has dropped, sales have gone up. Sony acknowledged their mistake using technology that new and have said they don't plan to try that again. It was a bad move.
The PSP suffered a marketing set back as a system, since Sony was trying so hard with the PS3 in the west. If it had been as popular as it was supposed to be, the memory card prices wouldn't have mattered. People would have purchased them anyways. It got a little worse when Sandisk marketed pro-duo cards, since they were a new entry into the market offering cheaper cards. Sony didn't drop prices though, oddly enough. I guess they were hoping for the brand to sell the card. They screwed up there, since in recent years, people have started to care a lot more about the money they spend. Sandisk is a well known brand too, so at that point, it's either preference or price driving you.
For the Vita, the memory card prices make perfect sense. You need a memory card to enjoy the Vita. The Vita comes with no built in memory. If you buy a Vita, that memory card's price is inelastic. You would still buy it even if it cost more because you need it to enjoy the Vita, and there are no alternatives. In the end, it's all a luxury, so the price will prove elastic in time with the introduction of alternatives. For now though, their memory cards will sell fine for those that don't want to wait. It's a rip off, but economically, it's one that makes sense.
Great post, although you technically don't need a memory card. Not all titles requirement. In fact, I think only a minority of Japanese launch titles (I think like 6 of the games) require it, everything else can save to the game card and what not.
Although I can definitely see the memory cards becoming required more as the system ages a bit more. Memory cards will be wider spread, prices will probably drop a bit, and the games will probably be a bit more advanced and require the memory card for a bit more room and such. Like a bunch of later PSP titles had data installs available.