I think Azure is great if you are willing to do it Microsoft's way and are focused on B2B markets where factors like compliance matter in a way that can actually disrupt your sales cycle.
Put differently, if you can get over the principled nerd stuff like "everything must be open" and break out that wallet, you can stand to make a lot of money without as much headache as the guy who decided to roll his own IdP.
Getting "cost sensitive" on Azure is how you lose track of the rabbit. The whole point in my view is to trade money for reduced complexity and time. It lets you focus on solving really hard business that others simply can't seem to find the time to.
calling it now