The biggest hassle and setback with creating for the pc is the quality assurance. It's a WHOLE LOT easier to confirm operational stability and marketable quality on a closed console (where it can technically be done with just 3-4 machines) than it is for an open platform like the pc (where it HAS to be done on at least 3-4 different operating systems - twice for x32 and x64, and that's not even touching ALL the hardware possibilities).
I hear this a lot but it's not really as bad as people seem to think. Firstly, compatibility testing is typically outsourced to professional testing groups. This is done a few times throughout development. It's not like the devs are constantly testing every possible hardware combination in existence. Secondly, console games have to go through certification, which is just as much hassle as ensuring compatibility on a wide range of PC hardware.
To demand or expect extra content or higher quality assets absolutely requires the pc market to generate greater revenue than the console market. That's ultimately what it boils down to. How would it make any sense for the developer to funnel loads of money and resources into features only a small minority of paying customers will even notice let alone take full advantage of?
Except an increasing amount of PC ports are getting PC-exclusive features so... yeah. If you want to maximize profit, you need to deliver the best quality product you can. With the growth of digital distribution (which offers higher profit margins and potentially infinite shelf life), the PC gaming market has become a lot more profitable than it was five years ago. Hence the increase in the number of games supporting PC-exclusive features. If EA wants Dead Space to sell more PC units, they need to put effort into the ports. It's that simple.