The original patent [1] actually separated the signal switch (ie the bit that the driver moved) and the release that was a magnetic link that was powered via a

The original patent [1] actually separated the signal switch (ie the bit that the driver moved) and the release that was a magnetic link that was powered via a ring on the steering column. So originally, the UX wasn't UP/DOWN = RIGHT/LEFT (which btw is reversed on RHD cars). There was a V shaped set of contacts with an arm that pointed to the right or the left and was held there by magnets until you turned the steering wheel. So it's more likely that someone worked out that mounting the switch on the steering column would save circuitry and expense than it was a UX/UI design decision. [1] https://patents.google.com/patent/US1620456A/en https://patents.google.com/patent/US1620456A/en