This opens the market for non-DRM type games, where there will instantaneous sales, en-mass, maximising profits, as there will be no expenses of upkeep of DRM servers, DRM staff, and anything related to the maintenance thereof.
Nah sorry! DRM/Steam = bad, very bad business plan.. in fact it's gross stupid and short-sighted, fueled by 'greed'... but that is normal for an accountant.
Not to mention the pirates who just bypass DRM/Steam.