I don't see Microsoft backing down from their SaaS push: it's necessary for authentication and authorization in all their Office 365 (or whatever it's called now) applications, also on platforms not running Microsoft clients. Beside that Entra is an OIDC server which makes it possible to integrate other SaaS applications in a domain which is near impossible to do if you only have local authentication.

Of course, you can still run local AD which synchronizes with Entra, but that means you get the worst of both worlds: you are paying for the cloud software but still have to manage your own servers.