I agree that as bike enthusiasts we see this differently that a lot of people do.

I think that something like the the classic english 3 speed (even if cruiser configuration) give the best answer (internal hub) Twist here to shift (if you are pushing hard twist this way...twist the other way to go faster), squeeze these things to stop.

The basic maintenance is an issue. Changing a flat if you have never done it before can be very intimidating, even supposing you have the tools. So it might be that we are focusing on the wrong thing for encouraging attracting riders.....maybe the need is for flatproof tires that ride if not well, at least OK but are not slippery, for self adjusting brakes and sealed gearing/chains, etc. is what is more important than how a bike shift.