"To keep the retailers happy. If they charged less, EB/Gamestop/Best Buy/Circuit City/whoever sells games would lose a whole lot of sales. Charge the same price, however, and Steam becomes just another method of distribution with no clear advantage over going to Gamestop and buying the game in person."
All it will take is for one dev release a major title via online distribution and the final sales numbers will speak for themselves. Yes the price to DL HL2 WILL probably be too high if no the same as retail. That was probably an attempt to head something like what's happening off. A case like this is going to make a lot of devs look into their distribution contracts in the future and should Valve win, this might be the touching off point for Online distribution. Personally if I had a choice between $49.95 at retail and $29.95 online, guess what I'm going to pick. The prices used are just as an example but you can see where this is going. This, like the RIAA, is an attempt to maintain their hand in the cookie jar, or better still, slow things down enough so that they can play catch up and figure out a way to gouge consumers in this new medium. Hence we have 99 cent music downloads which are still laughable because you'd be paying about the same to DL a whole album as you would pay retail. This is going to be a long, ugly fight. I wouldn't expect to see HL2 until this is all resolved.