Some things go deep, true. However most businesses don't use most of Microsoft products - even the ones that do, the usage of the more complicated products is far more minuscule than imagined by e.g. CFOs, etc.
The real thing keeping many "in the fold" as it were would be authentication services.
Which are overcomplicated and probably easier to manage without...
We’ve looked into FreeIPA and similar options, but honestly, nothing really holds a candle to Active Directory yet.
There's still a few that don't have direct equivalents, but the list is growing smaller and smaller.
what is state of the art today that compares to ActiveDirectory (not talking azureAd - or whatever they call it these days) ?
It's a rigged monopoly and has nothing to do with a market economy. Once you have been forced to use Windows, you are doomed.
What's something that AD provides that this does not?
It certainly sounds like an (almost) drop-in replacement.