The bad release of games for the PSP has little to do with SOny. It' s mostly up to the developers and publishers which games the PSP will get.
But I feel that the PSP has got quite a lot of good games. Pretty much as many as the DS, Here are some games I think are part of a good list of releases of the PSP (I haven' t played all of them though)

Kingdom of Paradise
Grand theft Auto: Liberty City Stories
Ridge Racer
Socom US Navy Seals
Virtua Tennis World Tour
Wipeout Pure
Lumines
Twisted Metal Head On
Mercury
Need For speed
Burnout Legends
Coded Arms
and there' s probably more games that I haven' t heard of yet.
And the list will grow, here are just some future releases that I' m looking forward to:

Battlefield 2
Godfather The game
Gran Turismo 4
Guilty Gear Judgement
Magna Carta Portable
Tales of Eternia
Ys: The ark of Napishtim
Fight Night
Me and My Katamari
Field Commander
Now, that' s a lot of great titles. I don' t know how much money you make but to me, that' s more than I can afford the nearest six months at least (I have to buy games for the other consoles too you know :P)
As you can see, there' s a great variety in genre. We have Sports, Racing, Action, Pussle, RPG, Plattform, adventure, strategy, FPS, Fighting, Multiplayer, pretty much everything.