Because if you don't then you can be sure that they will never sell.
And Linux is the only game platform without garden walls.
And Linux is the only game platform without garden walls.
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.
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.
What do you consider a garden wall? Anyone can create and publish a Windows binary without permission from anyone. It might even be possible to do this from Linux, using 100% GNU tools, though I'm not entirely sure about that.
Such binaries will create a warning if they aren't signed, but from a user's perspective that isn't materially different from requiring a "chmod +x".