it came way too late & could never catch up on features & apps
the biggest power plays (UWP apps, continuum, etc. that really leveraged Windows on the desktop) came too late. If W8 and WP8 had shared apps, it might have been different! By W10 the phone project was dying and so was touch on
MS charged brands money when Android was free
it was too different. We techies love a new paradigm & are happy to experiment, but normal users don't