That's actually simple to answer. Before the Internet arrived, you had to sell to the main market, anything else was guaranteed to lose money. But when the Internet arrived, there was gold in something called the long tail of Internet commerce. Suddenly there was a great deal of money to made from selling to niche interests, even ones that were ultra-niche.
It parallels how holding extreme views meant that rather than being isolated, a very odd person would find thousands of similarly odd people around the globe having those same views.