They have a few legacy things working in their favor. Hardware compatibility is one, but seems to be a thing of the past now when people don’t care. Application compatibility is another, and that is with Windows, not with NT.
And they don’t have to change the core parts, because NT is fine. Windows is not, it’s a heap of legacy, but it’s not realistically replaceable.
Unless they develop from scratch a new subsystem, like Embrasures or Walls or Bars, and gradually deprecate Windows. Doesn’t seem very realistic too, but if they still were a software company and not a malware company, they’d probably start doing this sometime about now.
Malware and porn banners are going to make this a feature always turned off.