Yeah, it just seems like it is hard to write an app that less-experienced users will both appreciate and use...much less pay for. After all, they may think MSN Messenger feels like it was written for twelve year-olds, but do they care enough to switch? Do they even know how to look for a replacement? (IM might be a bad example as nobody wants to pay for a client on any platform, it seems.)

OS X appears to simply have more of a tradition of independently-written, beautiful software.