Also, as we have seen since Nadella took over, Microsoft is a services company not a hardware company.
When they were a hardware company under Balmer, they got slaughtered.
Nadella realized that Microsoft was too late to compete in the phone market. It took them what, 3 years to even respond to Apple and 2 years to respond to Google in the phone market? Then it took another few years to even catch up feature wise.
Microsoft's current strategy makes far more sense. The hardware they produce is to demonstrate what is possible with their software and services. Basically, their in-house developed hardware is an example to all the oems.
Seriously, remember oem hardware from like 3-4 years ago? It was absolute ****. Nobody had hardware as beautiful as say the xps 13.
They know they can't "win" the phone market. So they will produce 3 levels of phones, show off their software and services and that's it. They have no expectation of competing or making money on it anymore.