Shipping a good and fast browser with Windows is perfectly fine, many will use it, some won't. Why do Microsoft care? The users are still running Windows. If anything this seems to undermine the value Microsoft place on Windows as a platform. Why not focus on making Windows better and if users want to use Windows to run Firefox or Chrome that's their choice.
I really don't see what value pushing Edge has to Microsoft. Are they just pining for the good old days of IE dominance? They dropped their own browser engine, so they obviously don't want to spend that much money on browser development, so why spend any at all?