On a cloud-darkened morning in March, a group of software developers fought their way through the crowds of tourists and puddled streets of Central London. In twos and threes, they filtered into an office on the edge of Soho, hidden in plain sight on a street of showy Tudor and neoclassical facades. They had arrived for their first day of crypto bootcamp.Five years ago, the Silicon Valley venture capital firm Andreessen Horowitz, also known as a16z, debuted a lecture series for would-be crypto f...