N connector is 1940s vintage. ?I think the difference
boils down to
materials. ?Nylon was first produced in 1935 and first found
commercial application in 1939, after the UHF connector had been
deployed.
N connectors suffer a fatal flaw - use the wrong plug in the wrong
socket, and you are screwed. Mixing 50 and 75 Ohm Ns will either
result in a crummy connection or a possibly ruined part.
--
Will