Old can be very cool, so can new. But with old you get the added rarity.
There was also a time when things generally were made better, using better quality materials and superior engineering and workmanship, simply because the industry was still figuring out how to make things well, and was yet to reach the point where their primary focus was how to make things cheaply.
All products and industries follow this curve, cycling isn't unique, the car is another obvious example.
There simply comes a point where they perfect the technology and then turn their focus towards cutting costs, and that's usually just before the penny drops - that building things to last is bad business.
Every product, every industry has a golden age, a short window wehn they were still craftsmen and creative genius's involved, before the accountants and managers took over.
The bicycle industry window closed sometime in the mid to late 1990s.
Picrel is a low - mid range consumer tier ATB. It cost £349 in 1987. Even accounting for inflation good luck finding that kind of quality in the same price range today.