Speaking as someone who does multi-platform software development (ARM, x86 *nix, Windows) and I can tell you that it's not bullshit and if any of you stopped to think for five minutes you'd realize why.
Conservative estimates put the time you spend fixing bugs at approximately 50% of development and every platform you have needs it's own QA, carefully honed test procedures and probably dedicated staff. Don't get me wrong, if you can do it properly multi-platform development results in better code for a variety of reasons - but we don't have to QA any other platform than ARM for our own internal development and if it turned out we had to support any of the others for anything other than internal use we'd probably need to double our team size.
The PC ecosystem has many things going for it but consistency isn't one of them - it's probably the area Microsoft have done the most actual harm to PC gaming - Modern versions of Windows come in Starter, Home, Premium, Professional and Enterprise variants in 7 alone, all in 32 and 64 bit versions and that's not even considering Vista,XP, DX9 vs DX10 or the myriad of different hardware options. It's not like Microsoft couldn't afford to add the 30 or 40 people necessary to get this game out on the PC but this is easily the most plausible and honest reason why they are not releasing it. Compared to supporting one or possibly two console SKU's the PC doesn't make much financial sense, consider the sales numbers from something like modern warfare 2, in Nov 09 it sold approximately 4.2 million units for the 360, 1.8 million for the ps3 and 170,000 units on the PC 1
. (Note, NPD numbers don't appear to include digital sales, but then Steam and all the other digital stores represent their own set of challenges as I'm pretty sure DSmart went in to previously on this very forum.
Now, if you want to slate Microsoft for massively confusing the market with dozens of pointless options (and Games for Windows, I doubt that's helped.) and Remedy being too cheap
to spring for a PC release that's fair enough I guess