Keep in mind that the PSP did not drop in price at all until just recently. $250-$200 wasn't a real price drop as Sony just removed the bundled accessories.
It's been around for over two years and was initially being sold at a small loss(I believe around thirty dollars), so manufacturing costs have probably dropped by atleast $100 if not more, so even with the recent price drop, Sony would be making a profit on each system sold.
Consoles owned: Saturn, Dreamcast, PS1, PS2, PSP, DS, PS3