You seem to be engaging in some revisionist history of Gatekeeper. The original concern was that it would be turned to MAS apps only by default, which it wasn't (and still isn't in Mavericks). By default the only thing you need is a free developer certificate to distribute apps outside the MAS (or to tell your users to right click to open, which bypasses the restriction).

Whether or not Apple does something in the future is a separate question, but accusing them of something they haven't done (despite several opportunities) appears more than a little biased.

Update: I am 100% incorrect about the developer certificate being free. You must be a member of the $99/yr Mac dev program to get one. So score one for "raising the walled garden" and I will gladly eat this humble pie.