This should really be a case study: don’t piss off your customers and developers before you have all your ducks in a row. Something that clearly others have not learnt, e.g. RedHat with their CentOS fumble a few weeks ago.
I think Microsoft has been having a bit of a change in attitude just because they're more focused on making money in software. They don't care where you buy it so much as they get a chunk of it somewhere. But what do I know.
Which allows you to just plainly sell games from your own website or use one of the many stores.
Oh side note, you can change your Xbox into a "devkit" and install basically any homebrew app. So technically, you can bypass its walled garden.