It's this thinking that you and several others espouse that brought about this problem, starting with a poor judgement call in December 2, 1999 from the Linux gaming community. (Read the second URL link or go googling for WHY that date was so important...) Because we couldn't wait for a Linux SKU, we're in the mess we're in now. Buying the Windows SKU is a vote for MORE Windows titles. Every time you do this, you make it just that more difficult for LGP, Runesoft, and others to arrange the titles you keep wanting. Bitching about the price delta on an SKU that's been out a bit for Windows and just out for Linux isn't going to help things any. Bitching about it being "old" isn't going to help things any. Suggesting "new" titles you want isn't going to help things any because the ENTIRE games industry isn't set up in a manner that you're going to get that the way you're griping about.
Publishers are going to make titles for platforms that will provide the MAXIMUM return on investment.
Pretty much all publishers care about sales numbers. In many cases, they think Linux is a waste of time past the server support. In some cases, the publisher is openly hostile towards Linux because they're courting MS' favor on X-Box.
When someone goes and tries to get a port of a title, in most cases, it's not the studio that has final say- it's the publisher. The studio has some say in the matter, but we're seeing instances of where the studio WANTED to do a Linux version and the publisher told them in no uncertain terms to STOP (Witcher and CD Projeckt...for a recent example thereof...).
Without having an edge, something like Valve being completely in our corner, we're going to need sales numbers for Linux titles to show to the publishers to see that they're not going to get stiffed like Id did with Q3:A. To do that, you have to buy Linux titles and not Windows ones. It doesn't matter WHOSE titles you buy, though buying from a large range of the people doing this (Greenhouse, LGP, Runesoft, Hyperion (if they ever get back to doing stuff...), etc...) will help more.
If you like the game and you're not running on Windows, WHY would you buy a product for the system you're not running?
Because it's cheaper? Fine. More power to you. Just remember... They don't view you as a customer unless you're running that SKU on Windows and they'd just as soon as not screw you in a New York Minute if they needed to do something to fix something or to get a better X-Box deal and leave you lying in the dust.