One issue of course is the current RVs complexity. A number of years ago I owned a 13' Aljo 1953 TT. There were no electrical appliances. Lighting was propane. That was replaced with a 17' TT 1974 vintage. It had electric but the only thing that ran off it were a couple of lights. You still accessed your water with a hand pump.
Now you have all of the alarm systems, water pump and most of all the reefer. Even when the fridge is on propane it needs 12v for the control circuits. So without either a genny or solar your camping time in a modern RV is limited even if you never turn on a light.
Solar is great in the summer in a spot that's not obscured by trees, but otherwise you gotta have a genny if you're going to camp for an extended period. Obviously this is just made worse by the fact that many campers want to live in the CG the same way they live at home with their AC, TV, video games, etc.