I think Mucrosoft agrees with you, but for them to go mobile, it was now or never. From what I read, they could not wait two years to go mobile. They would have been shut out.
I think it’s too late. Between Apple and Android, the market is set. Unless Microsoft comes up with something exceptional that works on really popular hardware, they missed the boat.
Microsoft became big by putting their operating system on the hardware that was the most standard (and way cheaper than Apple). I don’t think that market is available on mobile devices.