Single select success stories are hardly representative for the situation of thousands of developers...
Just think about the number of games that didn't get an offer like that, possibly just as good or much better games that just happened not to fit into what MS wants to "sell" right now, or devs who preferred to work on their games instead of setting up shop in some expo (or who just couldn't) - or devs that simply aren't in the US, which is basically the majority of developers.
That said, the fact that apparently developers are paid upfront instead of just "per play" is an improvement upon the Spotify-like deals.
However, make no mistake here, if this subscription thing ever became the standard, these deals would be a thing of the past as MS could now expect everyone to just go to GP (or similar services) for free and hope enough people play to make any money with it via.
As long as it stays the way it is now, I think it can be beneficial to some, while it won't mean trouble for too many others.
Another thing to bear in mind is that MS is well known for bending the knee to any and all outrage mobs, no matter how
small or ridiculous.
Therefore, any person with opinions that aren't extreme-left is basically barred from ever appearing on GP or forced to silence themselves for eternity just in case they work on a game that could come to GP.