Brit bikes had gear-change on rt. side / Japanese and most since: versa.

Turns out that.. (via many physio tests) the delicate matter of balancing braking ... works best with the Brit convention. (As on Vincent, Norton, BSA etc.)
L. foot on rear brake + rt. on front: was a naturally coordinated pair.
Never the same on the Japanese arbitrary change, since..
Net effect since: reduced effective reaction time. DUH.. beancounters.