Based on what I can understand from the tidbits of information I have read over my life, the traders within the stock market are comfortable where they are and they don't want to move to something that becomes unpredictable, like Bitcoin. While they do see the big pumps within the market, there is also a fairly high chance of the market stagnating for a period of time. The pumps are relatively unpredictable, so it's not like they can use the same patterns or techniques that they get from their forex market experience.