Anything old moves into the "antique" and rare collectable world and the prices rise because demand is greater than supply.
Fender in pre-CBS days also had variable QC, but the good ones were so good that no one remembers the dogs. In the CBS days Fender were primarily about making money so many of the changes were not good for quality. A lot of the good pre-CBS instruments have been snapped up over the years by a generation of studio players.
But. . . . electric basses are very cheap, even the expensive ones, when you compare them to the prices of other instruments. Collectable electric guitars can range into the hundreds of thousands of pounds, and most concert grade classical instruments will start at house mortgage levels.