It depends which "interesting people" you're talking about. I'd say investors like Peter Thiel (*spits on the ground) leaving the company were a key sign that it's past its prime.
For reddit, it doesn't need to be a middle finger from everyone. It needs to be some critical mass - and not even a critical mass of users, but of key content creators. However, all the bots and fake stories on reddit will likely help it limp on a while longer.