Still? I thought they had spun off their mobile hardware division and were instead mostly focusing on mobile software. Would make some sense for them to try to do the same thing they did with PCs and IBM back in the day, since the OS is already open source (mostly).
The rumors are they're still doing one last ditch, Surface Phone due to the growing Surface ecosystem that is making them money and people liking it so far.
However, they're not going to release that until they finish the CShell that they're working on the past several years.
Which makes it interesting for them to have an OS that won't lock particular software out in a play akin to what MS is trying to to to Valve by using their monopoly, a dogmatic Richard Stallman approach to this would ironically save them from that.