Isn't it more or less the same already? Most profits nowadays come from the post-launch DLC sales, not the units sold at launch window, that's why games launch unfinished, and that's the reason we see games dropping down the prices sooner than ever before, it's all about building a large playerbase as soon as possible. Which all makes sense since spending a few bucks every now and then is much, MUCH easier on the wallet for most people than paying up front the full price, which at the end of the day turns out that people actually spend more, way more than they would otherwise, as seen with the mobile market and F2P titles (especially the latter is giving a tremendous competition to MP-oriented, fully priced titles).