For us it's not about recouping. It's more about noise and fuel. Running a generator is about as expensive as you can do it but that doesn't mean it's bad for you.
It depends on how much power you need. It's like money, it's often easier to conserve than to get more. So if you don't need a lot of amp hours returned then the generator is fine. I have a 1000 watts and often use more than it can produce. I'd be running a generator all day so the solar does provide a cost savings for me but I don't know the numbers.
I want to be just as comfortable in our RV as our house so it takes a lot of power. If I didn't have solar I'd probably sit in a park and only boondock very little.