Azure AD is much better for a lot of companies in the long term than regular AD. No more FSMO, spending weekends troubleshooting replication errors after dcpromo, or wondering why the heck Microsoft wouldn’t enable the darn AD recycle bin out of the box. If you don’t need LDAP and your apps all support SAML, it really is better. And cheaper, since it’s free with anything you buy in Microsoft 365 (No more CALs that only work for a single release of Windows Server). And they have fairly decent zero-trust in the form of Conditional Access, which is like an extra dollar or two per user per month, and is included in many of the higher plans.