there are advantages in newer stuff, like disc brakes, the wheels that weight under a kg, or derallieurs that change gears more reliably etc. Or simply geometries that are more suitable for riding all day long.
There are, indeed.
However, there can be disadvantages to all those too. People tend to focus on the positives - there's no shortage of them highlighted in ads, articles, videos etc. I'd encourage people to think also of the disadvantages which are rarely so obvious.
I've met the poor guy having to pay almost as much as my bike cost to get a tiny part to fix a disc brake leak. And I've found the most wonderful camping spots that I never would have considered (or enjoyed) with an expensive bike. I can load an extra 10kg in water when I need to without worrying about wheels folding. Then again, my rim brakes eventually wore out my rim.
Swings and roundabouts. We're all different.