Oh, not arguing Steam is an awesome tool in generating more revenue for the publishers. But it didn't "solve" the DRM problem. It mostly showed that it's a red herring.
(Steam itself is also DRM, but AFAIK easily broken so more perfunctory).
I guess it depends on what the DRM problem really is. If the problem is that companies don't make enough money because of pirating, then Steam did solve the problem, because they make enough money despite pirating.
(Steam itself is also DRM, but AFAIK easily broken so more perfunctory).