Indeed. I didn't realise how "open" microsoft's platform was until iOS/Android came along. Now the old open platform model looks to be fast disappearing without any protest from developers. 30% revenue share for something that was free until now is a big deal.
Regarding Linux, the centralisation is at least justified (convinience, security). Furthermore Linux provides full freedom to ignore/bypass it. Not true with iOS/Android/ Windows 10 UWP.