A higher cost can imply better quality control as well, meaning that on average, a sample you pick is going to be better constructed. Sure, you can luck out on low or mid range basses (as I have), but it is less likely than if you spend more.
The best bass I ever played is an alembic, and the thing is pefect, although I do not have any need for it, I still play low and mid range basses because they absolutely do the job. I think we have just been spoiled by technology and the possibility of perfection in certain respects, that we did not even stop to think whether it is needed in any sort of way.
It always boils down to the age old question whether more money makes you more happy. Except for, that question has been answered already - people are basically as happy as they can be once they've taken care of the bills and have access to some small luxuries. Past that, happiness vs money is really really diminishing returns.
The same thing can be said of high quality gear - past a certain point, it won't make you happier or play better. Or if it does, it'll be marginal or short lived
A korean made mid range bass nowadays is very likely a better instrument than whatever was made 50 years ago, american or otherwise, I can assure you of that. That's just how technology works. It gets better and humans are replaced by machines, and suddenly you're in a position where the only thing pushing certain ideas is either tradition or nostalgia.