I've talked about this on here before, but we think the solution is an auth layer built on top of credit score through an intermediary like creditkarma. The score itself doesn't really matter but it does solve big problems.
Plus, if you wanted to implement a filtering system for users, I personally would rather trust reviews / comments from credit scores over 650, they have less incentive to be astroturfing.
But yes, I think your conclusion is correct. This is the only way.
How is that creditkarma accumulated? By other "users"? Does the intermediary guarantee, the this account is a valid person now and always, and not sold the account or not stolen? I mean, we will always need some middlemen I guess?