Every few years someone is faced with the task of integrating a Meteor application into an environment where the user logins are handled using SAML, see for example SAML in Meteor in 2022
Having recently started my PhD, I see a lot of SAML integrations in universities and online libraries for academic journals, so it may be more widespread than first thought. Perhaps it would also be interesting for Meteor as an application platform to offer such an integration more officially.