Reddit is 16 years old. It's one of the largest sites on the internet by views, users, time on site, any metric you would care about. They have something like 500 FTE's, which is tiny compared to lots of other sites with far less traffic.

It's basically the perfect combination of high traffic and low costs, and they have raised close to a billion dollars in funding. If they aren't profitable now, they are very unlikely to ever be profitable. I think it's likely they will sell to one of the big players (I would guess FB) in the next 5 years or so. If that goes the 'usual way', whoever acquires them will immediately let the site fall apart and eventually shut it down, and in the meantime a new hot reddit/digg/slashdot like site will emerge to take it's place almost overnight.