You might get some figures from people who cam seriously, but I think you could do with knowing for yourself. Why not commit yourself to do some more hours and see how much you make.
I don't think cam should be any less dependable than escorting. You might have a rubbish day on cam, but you could just as well have a dead week as an escort, and as long as it works out right over the weeks it's ok. It's a bit more annoying with DirectCam because you can't get on with stuff while you're waiting in freeview, but at least you don't need to leave the house or let anyone into yours.