Is this going to end up a big wet fizzled out nothing burger?
I think it might be something close to that, at least in the short term. The police investigation may go nowhere unless (a)they get the victim to step forward and cooperate and/or (b)they find such a preponderance of evidence that they can make a case without the victim's cooperation. The latter is probably very difficult for such an old case. The former... who knows?
It's possible that there will not be a clear outcome, and he'll focus on that case in the hopes that people will forget the stuff he already admitted to. It's that stuff --the stuff in his book and in his video-- that will be a stain on his reputation until/unless he owns up to it. He may well fade into irrelevance. Spending hours per day trying to keep his YouTube comments sections clear of mockery and derision will be the least of his issues in the long run.
He's also cut off from many (all?) of the avenues of activism that he enjoyed before. Who will want to be involved with someone who has such a bad reputation (and again, this is just from the things he admitted to)? He no longer lends legitimacy to someone's interview show or documentary; he's an embarrassing distraction to the work they want to get done. He's the guy who treated his wife like dirt for many years, and any new information that could come to light would only make him look worse.