And I boycotted steam's avidly for the first years because I knew what will happen and how they will kill physical games and the 2nd-hand-market (and the lending of games) for the poorer.
Caved in with left4dead2 finally and am now at like 20k games. And was right. Both markets are basically dead and I joined the devil.
At least, as long as they're not going public, they enrich gaming a bit, as they're not just a sales-platform like epic.