How would that help? Hardly anyone cares for windows the OS, instead they care about "it runs MS office, autocad, muh gamez, photoshop, active directory, powert

How would that help? Hardly anyone cares for windows the OS, instead they care about "it runs MS office, autocad, muh gamez, photoshop, active directory, powertoys, ...". At best you will get the same situation as with android: Manufacturers will ship skinned versions of windows with some extra features. Actual forks are almost non-existent except for amazon and maybe the Chinese market. All the actually important stuff will still be closed source, e.g. google play.