I would immediately agree if the gangs were utterly fragmented away from each other.

However, many of those gangs simultaneously constitute an asset for the government of their respective country.

Case in point: In Russia, things take the form that the government lets the gangs do their stuff, but they have to attack government-chosen targets every once in a while. So there is already structure for coordination. What it would take is for the Russian government, or maybe even just one of its rivalling intelligence agencies, to conclude that making an example out of Britain has become important. Still more interesting game theory lies here: Russia's government and agencies needn't even hope to participate in any ransom payouts at any time – just perpetuating the gangs' damaging of European economies is already heavily in their interest. They have a cyberwar budget anyways.

However, I know far too little about the economic magnitudes involved here to say anything with certainty.