There's more people here still than you'd think - when threads get started, the activity within them is not super low. Of course activity is decreasing over time and it's hard to see how that decline will be reversed, but I know from experience that sites can survive for a long time in a not-quite-dead state.

Of course only you can decide whether it's still worth your while to come and post here, but I'm not sure what you' aim is when you ask if it's time to abandon the site - is it just that you want to save Ben the expenditures of keeping it running? Because that's his own choice, surely. And if not, what's the point of suggesting to others to join you in abandoning the site? That would only make sense if you join it with a suggestion to migrate en masse to some other site.