They have very few moving parts. I am guessing they are switching battery pack modules out so it's not that hard. Theres battery packs, motos and basically thats it.
There are a lot of moving parts in the suspension, the transmission, the battery cooling system, the AC, the power windows, power steering, all the other comfort features like electric seats, electric tailgate, ...
Just because it doesn't need an oil change doesn't mean that it doesn't need service.
Theres no transmission, the battery cooling system isn't a moving part, the AC has one moving part, power windows have 1 moving parts, power steering have one moving part, electric components aren't moving parts.
Moving parts are mechanical parts, electronic, and pumps because of simplicity work for longer.
Just because it doesn't need an oil change doesn't mean that it doesn't need service.