Wouldn't any sane SSO implementation let you recover and switch to a password simply by proving ownership of the email address via a challenge email?
If I ever lose access to my Google account I can just set a password through the "forgot my password" feature (I've noticed this is often also the only way to set a password if you create an account through SSO with some websites, but it does work). The convenience of SSO with an escape hatch as you say.