My first company went through a similarly deep "trough of sorrow." We launched riiiight before the first dotcom crash, limped along for a year or two (product doing well, revenue not so much) then us founders went out and got Real Jobs. But the product kept chugging along and a few years later we came back with some monetization ideas and things took off for real, leading to an acquisition almost 10 years after starting it.

I think the moral is that if you have a working product with no revenue, it may find a way if you can give it enough space and time. Some products need a lot effort/money to keep going, but if your company is built like a cockroach and you have a product that people use, don't shut it down or throw it to the wolves unless you absolutely have to. You don't hear a lot about these phoenix-like companies, but it's good to know that the end isn't always necessarily the end.