Let's step back. The problem is hand brakes. We've all focused on the brakes. Maybe the issue is hands. Perhaps we should be using our brakes, but not using our hands.
There is general agreement about the inadequacy of coaster brakes, so lets reject that as a non-viable solution.
Shimano has introduced electronic shifting. Can electronic braking be far behind? Once that hits the market it's only a matter of time until thought controlled braking makes a .... should I say break through?
This advance will free us to use our hands as the gods intended: To throw rocks at each other.
Until then, I will use my three fold system: Drag sneaker on road, put other sneaker heal on back wheel while I back pedal the coaster brake and use my "quad brake lever" that activates both front and rear calipers and disc brakes.
This leaves me one hand still free to flip off the crazy people who won't see things exactly the same way I do.