Regulation solves this. I hate to say that, as so much of tech regulation is a ham-fisted disaster that misunderstands the problem and creates even bigger ones, but this is really a very serious problem that can ruin lives, and regulators really should step in here.
I’ve known a couple of people who have been through this experience, and one in particular who not only couldn’t get back in to their account - but had no way of knowing if someone else was able to get in to the account later. They’ll never know. It will never be possible to know. The kicker is that they could never have their data deleted due to the same problem. And no amount of help or time spent with chat support ever changed anything.