I think the other replies to you are probably correct, but I also can't help but think that a lot of the small/mid size businesses that use AD for Auth, have been on prem for years, and weren't really planning to make a move very soon until the Pandemic hit, have sort of run face first into the fact that they're really stuck with Microsoft now and when Azure AD goes down, their whole business tends to go with it. I don't think there's an easy solution here, but I've seen some places coming face to face with this reality and there's been some very mixed feelings and not many alternatives.
Fair, but even still AD only gives you a piece of the puzzle when it comes to authorization. You still have to do all the modeling and implementation inside your app and map it to however that's stored in AD.
