Firstly, yes I do know that. Windows Phone was before Satya and the telemetry ramp up and was a quite marvellous platform compared to the alternatives on the market. Unfortunately they fucked it up switching from CE to NT and burned all the developers in the process.
Would it be different? No. Should it be different? Yes. They had a unique market position and squandered it. Microsoft had the whole world as its oyster and chose the bad path every time.
As for GNU/Linux on phones, only when they make a usable non Android distribution which AFAIK does not exist. Until then I'm going to have to sell a piece of my soul to the devil (Apple) who actually spend enough time making something fit for purpose to make it usable without incurring a major societal disadvantage.