I think he was broken by "Games for Windows Live" on PC. They had to integrate it in Gears of War, and I think a lot of the industry saw it as Microsoft trying to steer the PC into being a MSFT only device. There was not much benefit for devs/pubs to using it, it was all good for Microsoft. He seems to want everything to be old school PC where anyone can sell in their own store and do what they want on a device.

However, it always feels weird to me on mobile since those devices were not really open and the maker always took their store cut. Epic knew this and got on those devices anyway, but then after Fortnite getting huge, wanted more of that mobile pie for themselves. That's sort of a generic take on mobile, as I haven't read through everything on this case.