I know nothing at all about bitcoin. But I do believe, the best way to beat scammers in general is not to ignore them, or to swear at them, it is to waste their time. For to them, time is of value, and if you waste that time it does impact their business model.
Hence I wonder... would it be possible to respond to these ransoms by paying a tiny, tiny, tiny. fraction of a penny? It must be so tiny that, even multiplied by millions upon millions, it is still nearly nothing, ie reward for sending 500 billion emails == 1 bag cheese&onion crisps.
If that were possible, the logistical overheads for the scammer would presumable become very unpleasant, plus law enforcement would have better chance of tracing by brute-forcing analysis of the millions upon millions of infinitesimal payments?