It depends on what you define as Black hat.. in my opinion black hat is something that is always ahead of the curve.. When the algorithm was just about keywords, Blackhat was about keyword stuffing.. When algos looked for PR and backlinks, Blackhat manipulated PR and built 1000s of backlinks. Then the focus was on content, BHW focussed on it too.. then social signals, BH manipulated the social signals. Then HA expired domains, then PBNs, media mentions and so on.. It doesn't matter what google throws at you, there will be a BH method to manipulate the results..