Valve "played capitalism so well they broke it" and now Steam can't be replaced
(www.gamesradar.com)
I would move on if a better alternative emerged. But at this point it's not just the store, but the utility. Steam lets me add whatever games I want from any source and use their interface to make controllers work, tweak graphics settings, etc. Hell, I'd say I like it better for that use than for the paid games. I don't see anyone else ever doing this.