In a recent video chat, YC partners explained how consumer startups are often a "tarpit" (seem attractive - "all my friends think it's a great idea", but super-hard to get uptake, scale and revenue). Whereas there's an endless pool of opportunities to solve business problems that many small-med companies would happily pay (a little bit) for, and it's much quicker to validate (see if other startups will use it) and monetise early (vs both consumer and enterprise).