Yes almost all modern cars have it to support steering. But if the pump, motor or battery is broken it can still be steered with muscle power.
The nightmare of every car owner is a bricked car which can not be moved anymore, even when its done by towing or pushing.
That's true though many of them aren't designed to be steered without the power steering operational so the more you drive manually the more damage you do.
I would assume this would be a similar system in this case. There's no way an unsteerable car would be allowed on public roads.
The very first planes were fly by wire... But analog wires Idfk lol . you actually had tensioned wires that stretch between the control peddles or yoke to the control surfaces... This is fly by cellphone. No actual physical connectionn. If the power goes out or maybe ... A bad connection, you are going to have problems. I would rather full manual steering give me back the big ass steering wheel. They are looking to speed up the whole ease of assembly and "repair". Much easier if its only a plug or two and a couple bolts to remove the rack and no slip joint, no hydro. No extra brackets off the engine which is already a accessory and timing mess of belts and chains.