As a developer we do not have final say in the sku plan for our games. That is the decision of the person investing the money, i.e. the publisher. We have much of the technology in place to produce PC versions of all these games, but there is still some more work required to make them shippable and that costs money. So far, our publishers have not elected to fund that work. Not because they hate PC Gamers, but because they don't see enough financial reward. Double Fine does care about PC Gamers, and we always push for a PC version, and will continue to do so in the future. If we ever get super stinking rich here, with enough money to fund PC versions of our games, then we will go back and make them ourselves! Oh man, wouldn't that be cool?
I reprint what was implicit to all us due to the fact that this was for some reason picked up as a story on Gamasutra, and any debate in the comments there might be of more interest than the ones indigenous to The International House of Three Readers.