To be fair, integrating with enterprise SAML isn’t zero-effort. There are engineers/IT on both sides going back and forth, and the provider is going to have to deploy a test environment for the customer, possibly debug things there, then there’ll be questions to answer about federation etc…

I wouldn’t do it for free, either.

But standardized SSO like Google or (presumably) Office 365 - yeah there shouldn’t be a tax on that.