I don't think car owners have to worry about this the first half million miles or so with these motors. Electrical motors last a long time. We'll know for sure in a few decades, I guess. That's how long it will take for a significant number of their cars to actually drive that far.

Also, compare this to ICE engines which experience continuous explosions, lots of mechanical parts, extreme temperature swings, etc. and still manage pretty decent durability. There's simply no base for assuming that parts like this wearing out and needing to be replaced is going to be a common thing.