From a technical perspective why isn't this a solved problem? Identity will always be a difficult problem, but being able to own your own face / likeness by demonstrating it should be technically possible right? Forced visual "captchas" something like "please take a photo standing on one foot and your finger pointed at your nose" Then once you own your likeness with "faceID" likeness similarity isn't it then easy to…
Not to mention the near future triviality of image generating AI being able to just recreate what you're asking it for a "capchat". I mean once it figures out hands that is.