No, they shouldn't.
Of course, there is no doubt that 3DS will be the beast. But PSP, even if it's not a winner on the handheld market, is a Sony's very respectable step. 60 millions consoles sold and counting, 35 million-selling games. Nice try anyway, I think! Even if Sony would quit from handheld market I will remember PSP as a good and successful console. Maybe Sony would try enter the market again, if there would be a suitable situation in the future.
Also a PSP's mission isn't over for me cause I'll have to play Parasite Eve: The Third Birthday! :D
P.S. Some people are already playing 3D games on PS3. Yeah, with glasses (glasses or non-glasses... in the situation with PS3 it is only depending on TV, not on a console), but they are playing. So maybe it is a Sony 3D-gaming pioneer? =)
