> Adding support for OIDC is not that difficult. I prefer OIDC over SAML anyway, but neither is that difficult.

Since it seems that you know what you are doing (and you've done it before), how about a blog post detailing the steps one would go through when writing some SaaS app for a client who wants SSO?

If it requires configuration on the user’s end then it’s no better than SAML from the vendor's perspective. We’d much rather choose specific providers to hook into, based on the likelihood of increasing sign-ups.