I think I'm in the minority with this opinion, but I dislike vintage gear. It's expensive to buy, but then also expensive to maintain, and you then have to worry about using it and ruining the value. So these aren't really for musicians anymore but collectors, and that's probably why they are being bid up. There is a lot of money sloshing around from all the printing the government did in those QE programs, and that money finds itself into all kinds of things, even vintage basses. If I had one I'd sell it.
Also, I think all the baby boomers dying in the next 10-20 years is bearish for vintage prices. Millennials and GenX can't really afford the prices they want.
I like new instruments, but limited runs. The bass I wound up buying is new but only 500 were made (it's the Magnificent 7 PJ bass). I also bought a Fender Jazzmaster where only 50 where made. I'd rather do that and pay a lot less for just as good an instrument then get involved in vintage (money pit I'd be afraid to use and ruin) since they're limited in quantity maybe they even appreciate. That's just one girl's opinion, though! To each their own.
The only exception to me are vintage amps because they are really hard to break so I wouldn't fear using it, and they truly do sound better. I never played a vintage bass or guitar that sounded or functioned better than a modern one.