Western Union? Scammers have had means of collecting payouts since the beginning of scams.

One interesting counter point here is that the money hasn't disappeared. Literally every cent that has been paid to one of these Bitcoin addresses can be traced through all future purchases by anyone on the internet. The money will, of course, be combined with other amounts as transactions occur but that doesn't kill the trail. If any of it does end up in a wallet which a government can tie to a real person, an investigator can start working backwards. This is no different from marked bills in a more traditional ransom payment. Not perfect, but proven effective.