if you license on the u3 engine you have to license on all 3 platforms, PC, P3 and xbox360, no choice in that matter at all, thats the deal when you sign up the engine with Epic, so if they bring it out or not on other systems they are still paying for it, from what i hear its 2 million for the engine, so thats $666,666 each platform, so if you don't bring it out on a platform you are chucking away $666,666.
Frankly i find the idea of spending hundreds of dollars on a graphic card just to play 1 video game ludicrous, each to there own, though i don't find it is odd as bringing a game out that only a small minority of gamers have the hardware to run it on even more crazy, thank god for console game sales, incidentally some publishers will not even talk to you unless you are going to release the game on consoles as they consider the PC market too small, is you have to buy a new graphic card at hundreds of dollars then I'm not suprised the market is so small.