I do not have an e-bike, I have never even rode one, but I have been an electro-mechanical technician most of my life. I got the impression the impression the OP "chose" not to ride the bike home. Not because it was impossible but because he had a load of groceries with maybe frozen stuff in it, and he had the option of using the subway. Also he may not be as savy about bicycle repair and maintenance as you are.

As I see it an e-bike only has 3 more things that can go wrong than a pure pedal bike does, motor, battery, or controller. That should not make for much greater unreliability and only if the bearings on a hub-motor go would it incapacitate the bike completely.

I would guess the OP's controller went south, Chinese made electronics are not the most reliable in the world. My fancy electronic controlled coffee maker died yesterday, maybe I should go back to a percolator and a wood fire?