Enterprise customers depend on legacy stuff that you haven’t heard of. And there’s enough of these 800-pound gorillas in the room that pay for enough of Microsoft’s bills that they have to listen to, that they can’t cut it. A behaviour bug from 2002 is actually used by, say, JP Morgan’s trading department as a critical part of their flow.

Also, the legacy stuff is literally decades of work and knowledge so unscrambling it is not really feasible.

They can’t nuke it because of the customers that rely on it. Microsoft’s job (and that of all vendors) is to cost less than a migration to another option.

Yeah I understand those legacy systems, but I wouldn’t expect those to be upgrading to Windows 11 for example. I guess that’s why I was suggesting a separation of “then” and “now” operating systems.