I have heard and read about a number of similar cases where people can get completely locked out of their account despite being able to authenticate correctly,

I have heard and read about a number of similar cases where people can get completely locked out of their account despite being able to authenticate correctly, because they lost access to some other required resource that Google decided is essential. I'm very skeptical about the utility of these types of security policies. I'm sure they prevent hacking in some cases, but they also greatly increase the chance of a legit user permanently losing their account which is a pretty freaking bad outcome for someone who has all of their email, messages, photos, documents and more stored in their Google account. Given the importance of these digital services I expect that refusing to provide support to users in this situation, as Google is well known to do, won't be legally tolerated at some point in the future. Unfortunately this won't be changing anytime soon, so the best we can do is inform others about the risks of relying solely on Google for anything important and hope people backup what they can.