As much as I like Steam in its current form. you have got to be kidding me.
Steam is buying their way to the top b selling product at or below cost. This will drive in new customers, creating someone out of nothing. Down the line it will be up to Steam if the wish to continue this route My guess is that they will ease up on the sales just like any other e-tailer startup does.
Newegg anyone? They used to have free shipping on all, and UBER cheap prices. Now places like Amazon, etc. at meeting and beating their discounts. Unless the markup on video games is insanely high, you should expect the same from steam. Then again, with no B&M there might be the headroom to do so.
This is the beauty of it. What you described does not need to happen. This is software not hardware.