In exchange for my loss of right of first sale, Steam continues with the aggressive pricing.
Not being able to resell games matters to me less when I can buy games cheaper in the first place.
This is especially true of archival titles, which (when I could find them) would often be a forgotten beat-up box on a shelf, with an ancient $39.99 price tag still on it.
Steam also does a good job with the price drops on recent games. If the game isn't something I necessarily have to have at $50 on release day, I usually don't have to wait too long for a price drop.
Obviously, price drops depend on the publisher, but Steam is a storefront geared toward price mobility, and Valve has created a model with their aggressive sales for other publishers to follow.
I hate that too, but the DRM has a very powerful positive side-effect: getting caught cheating online means you lose your license! The only time you see exploits in TF2 is during the occasional free weekend.
It's awesome aside from that though.