You don't overestimate the average computer user. A computer user does not think in the same way you do. A user may know what copy and paste does in Microsoft WORD, but they do not see this as anything but a feature of Word. They don't think it is something that is generally applicable to all text fields. That concept is naturally unintuitive, it's something that has to be learned or discovered.

I'm technically very saavy, but open id is something I really don't want to use. It sounds complicated, it's difficult to use, it seems risky, and most importantly, it does not offer me any advantages.

It's a silly idea pushed by technologists who are out of touch with what the average person is doing with his computer.