Fully electric RV, diesel generator, RV of the future?

We've seen all electric Class A's at RV shows. They have eight house batteries, a household type frig, etc. I'm assuming they had solar panels on the roof, but I don't recall. Obviously, it isn't the ideal rig for boondocking, but at 45 ft and a price of over $500K, the owners probably wouldn't want to do much dry camping anyway.

As for propulsion, a very large diesel is the only good alternative. A quiet diesel generator would keep the batteries charged up.