Instruments becoming collectable, can be the curse of great music. They get priced out of reach for the working musician.
It's said that the string sections of the top orchestras don't sound as good as they used to, as the players can't afford Stradivarius' and other similarly great instruments any more. Rather than being played, they're sitting in bank volts owned by collectors, not players.
With the value of old basses, there is supply and demand, but equally who plays them? If someone like Pino Palladino had pickup an Ibanez Musician, instead of an early '60s Precision, you can guaranty that the value of them would go through the roof.
Assuming that Stradivari do sound better than your average quality violin today, there is one big difference - collectible Fender basses from the 50s' and 60's don't sound better than common basses today. Quite the opposite, IMO.
And Pino Palladino could have picked up a Musician and nothing would have changed. Sting is a bazillion times more popular than Palladino, is well known for playing an Ibanez Musician, and that didn't make a difference.