Ancient LDAP is probably the best they still offer. A far superior way for internal auth and vastly superior for companies that need on premise infrastructure. Nobody wants internal apps that auth through AWS or GCP.

I hate registering a shitty app and use their modern auth flow. No security gain for additional maintenance.

For that matter, this is a main reason why Windows is so established. The logistic problem of distributing user accounts on several machines.

And no, a virtual and slow cloud Windows is not an alternative for anyone that wants to be productive.