Ya the 360 released a year earlier and considering sales from launch they are doing better than the 360 (even with 2 next-gen consoles to compete with).
http://vgchartz.com/hwlaunch.php
Last time I checked they are toe to toe (equal) in sales in 2008....so in my view they are doing just fine, especially with a higher price tag.
No devoloper will quit making games for the ps3, so I have nothing to worry about. From sony's viewpoint....I'm sure they will turn a profit. Which honestly is all they want.