I think the major point is that developers (understandably) make games for consoles for a higher profit, since the console game demographic seems to be much greater than the PC game demographic.
Let's face it, fellow PC game players: We are often assumed to be nerds, while some frat boy "headshotting noobs" on an X-Box is, for some strange reason, considered "cool" by the general (or at least the more perceptible) public.
For consoles, there are quite a few limitations:
1) Control interface
This one has been brought up quite often in the course of this thread. A gamepad just has far less keys than an average keyboard, which is a good thing actually. Keyboards were originally designed for typing texts, a job they do really well. Gamepads were designed as a simple, easy-to-learn interface for playing games, a job they do well, too.
Now developers for the PC platform are using the keys meant for typing to control games. They do this job surprisingly well, too, and since there are so many of them (105 I think, I didn't count), a for practical applications unlimited number of commands (especially when using modifier keys like Shift and Control) can be executed by keyboard. On the console, you get... I'm not sure... 12 I think, and five or six axes (on an XBox gamepad, the shouldter trigger things work like one axis in Windows, but can execute simultaneous commands, so I'm indecisive). So, in order to make a game work on a console, you have to use a limited control set, often relying on context sensitive controls (taking cover and picking up objects can be the same button, depending on your situation).
Since most games are published on consoles AND PC, these controls are often just translated to the PC, making PC players feel constrained, since they are used to complex keyboard layouts for games.
2) Screen size
While HDTVs are great, they are usually still inferiour to a really good computer screen when it comes to contrast, forcing the games to use clearer-than-life imagery. Additionally, you are usually pretty far away from the TV, so the screen text has to be bigger, while on PC monitors, the maximum distance would be about 1m, usually lower, making even small fonts easily readable on the PC screen.
So if a console game gets ported to PC, the players get a brightly-coloured interface with huge text on it, which is perfect for a far-away TV set, but feels childish and unnecessary on PC. This problem could be - but usually isn't - solved by using a different interface on PC.
3) Demographics
Most PC players have a certain seriousness when it comes to games. Most PC players have no real problem investing a lot of time in quests, for example, while lots of console players are more casual players, looking for a game they can start, accomplish something (quest, level, whatever) and switch the console off.
This, of course, leads to games which feel more simple than what PC players are used to.