Bergen: There's so much trepidation in doing late stage rounds that no one wants to be the last guy in, because you're not sure if the next guy is going to fund the last round. Bergen: You're making a social market bet, not a bet on the team or the business or the value. It's that there's someone else that's going to lead the next round. And we need investors to be much more aggressive in holding folks accountable," he says.