I would suspect they are looking at two things:
1. User base. If you sold your game to 25% of the current PC gaming audience, you would not make as much money selling your game to only 10% of the current PS2/console audience.
2. Limited, fixed hardware. This can cut down on development time, greatly minimize support issues, and you can often spend less time trying to fill the potential of the hardware (you have to work a lot harder these days to maximize a x800 whereas the PS2 hardware is quite old by now.)
Yes, there is more to this, but these are generalizations.
Avoiding the expectations aspect...,
Ray
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"You're worried about morals? Beat them senseless and steal their clothing, dammit! Steal! Steal!!"
http://users.ign.com/collection/RayMardenhttp://www.dvdaficionado.com/dvds.html?cat=1&sub=ANF&id=ray_mardenI love you, mom.
Everything is awesome!!!
http://www.kindafunny.com/I love you, mom.