Utopia: Why doesn't Tony quit?

It's a question I find myself asking while watching the latest season. What possible reason could he have for sticking around, despite the fact that it must be extremely clear to him that he cannot achieve any of his goals. Unless he actually does achieve some things, but we don't see it?

I was reminded of Yes Minister and how, despite the general impression I got while watching it being that Humphrey wins and Hacker loses, Hacker does actually win sometimes. And that's important. If he lost every single time without exception, he'd be a fool to keep trying. And the show would not have been as good.

Utopia, at the moment, is becoming a bit hard to take. That question - why doesn't Tony quit? - is on my mind constantly. It undermines the verisimilitude. He's obviously got other options. Why wouldn't he quit? He must win sometimes, but if he does then why don't we ever see it? The writers of Yes Minister knew that there was humour in seeing Hacker occasionally get something past Humphrey, and that it wouldn't make sense to have Hacker be completely impotent. He's got to have a reason to keep trying.

I keep saying that Tony must get the occasional win off-screen, but that's not enough. Things that don't happen on the show, don't happen. That's just me making stuff up to cover for the show's flaws. The fact that one can imagine a solution that the writers could have used doesn't make up for the fact that they didn't. For it to be in the show it has to be in the show. Tony has to win sometimes, 'cause if he doesn't then he should just quit. Nat as well, obviously.