It's true that every service has to deal with the same policy and lockout problems, but that doesn't lead to the conclusion that the risk is the same. I pay for FastMail because 1. if something goes wrong, I can reach a human without needing to write a viral blog post first. Other services pay for a customer service department. 2. I trust FastMail more to not shut down their product because they got bored. Sure Gmail…
"I can reach a human" is a huge security vuln. I don't want people social engineering my identity provider.
The opposite of that is, you do not have a way of recourse, ever. Even states have some.