When Leo Fender introduced his electric bass in 1951it must have been obvious that a large potential market for his instrument were the many double bass players out there and the opportunity to downsize and be heard. So why did it take until 1970 for Fender to produce a fretless model?
Surely many more existing upright players would have been attracted to the electric bass had fretless versions been available from the outset? Given that the fingerboard starts its life without frets in the factory, it would have been cheaper to promote the P bass as fretless with fretted as an option.
So was it because Leo had the mindset of a guitarist or just had poor marketing advisors?
For instance, when Jaco Pastorius made playing fretless bass popular around 1975 using a de-fretted Fender Jazz bass, Fender still didn't seize the opportunity and offer a similar model fretless till the mid-80's.
I'm not knocking the introduction of the fretted electric bass but had it started as a portable fretless alternative to upright, maybe the evolution of bass-playing would have taken a different journey.