Actually apart from sanctions hitting Russia hard , there is indeed a somewhat true conspiracy theory about how many Russians ended up in this biz.
Russian underground was devasted by internal war back in 2010-2011 widely covered in media internationally and some of it still follows, the scandal of elections meddling in USA in fact in reality dates back to events of an internal underground conflict inspired by FSB and FBI moles within FSB itself in 2010. There were USA academic researches about the subject (for example professors Neal Weaver and Stefan Savage done a lot on the subject of acadimical research) along with crazy whole NY Times bestseller books written about it.
The crazy Russian bitcoin/altcoin/blockchain development influence is somewhat related to that war fog as well. Many Russian underground programmers and webmasters and guys alike were trying to find a save heaven in 2010 trying to get away from the devastating conflict within and found such a save heaven in working with stuff related to Bitcoin as Bitcoin stuff was not involved in the global conflict.