Almost all connectors in use on computers at the time USB was introduced were already keyed, and a fat lot of good it did us. Ask anyone who tried fumbling around behind a three ton CRT monitor or computer case -- even with the keyed connectors, feeling for which side was up, getting anything plugged in without eyes on it was already nigh on impossible.

What the USB A connector did do which was new at the time was introduce a connector that did not have any protruding pins on either the male or female end, and thus theoretically at least could not be damaged by fucking up the insertion. Unlike any of the then-common D-Sub connectors (VGA, serial, parallel) or DIN (PS/2 mouse and keyboard, Apple serial, S-Video, etc.). USB didn't even have the little clip to breal off like an RJ-45 Ethernet or RJ-11 phone line connector.