I think that's because Tesla and Rivian are the only two brands' people trust right now, especially Tesla. Look how bad Ford and Chevy flopped with theirs. There is no proven trust. I don't think there ever will be.As it stands today- Most do not want an EV, the ones that do mostly want a Tesla. I think that's a fair statement.
Just think how many complaints there would be if more people actually bought them.