I had the priviledge of meeting Leo Fender in 1979.
So here's the (rather modest) view from the man himself.......
Simply because the Fender was the first mass-produced bass guitar to 'catch on', it became the sound that folks assumed the electric bass should be.
In other words, he thought that if Rickenbacker, Gibson (insert any other make) had beaten him to it [i]they[/i] would probably have claimed the prominent position and others would, as likely as not, always be playing catch-up.
OK, troll on......