I saw this passing by a lot of times, but either I misunderstand the pricing or it is indeed 'enterprise' pricing. Because even small sites I launched have easily 10s of 1000s of users and some have had millions => I cannot see this pricing work at all on any of those without me closing the doors (having margins that are just too small or just making losses) vs making a really good living.
We have a microservice for this which we use. It's internal and was extracted from systems/practices that grew over years. Basically it works like Auth0 many of the bells and whistles, but it's just a service in our network. And, probably not a surprise, TCO (cost of running/maintaining it) is a rounding error (few $100/month) for millions of users.
