Then show me the profit they make on each unit.
That list is pretty pitifully thin for a Console in the prime of its life, especially when I'd count a third of those developers as mediocre list fluffers. And most now only throw scraps to the PSP with the exception of a few shining exceptions. Capcom has grown weary of the PSP calling it a failure and many of those developers have shown dissapointment in the PSP's performance. A good number of developers also threw scraps to the N-gage.
Defend the PSP all you want, but this isn't the PSP's first year, this is the PSP in its full stride. You can only make so many excuses for a handful of worthwhile games on a piece of hardware that obviously isn't being bought for its games. If this is in any way looks like a successful thriving gaming console to you, then you have my pity.
@Game_Boy, even if PSP hardware sales are increasing, are the software sales?