Steampunk. Vinyl. Tubes.
All have some popularity, but why do they? Sure steampunk has a neat style - the time setting of it had few if any synthetics, which limited materials, but that seems to come across as classic style. There is no doubt that had there been synthetic materials available they would have been used. We know this because that's precisely what happened in our history. Cellophane, as one example, was a big enough deal it got written into songs:
You're the purple light
Of a summer night in Spain,
You're the National Gallery
You're Garbo's salary,
("You're The Top" - Cole Porter)
But people go to steam (and antique gasoline) shows. And there are records - and even tape - in use. Vacuum tube equipment is rarely seen now, but it's there and some new stuff (kits, generally) is still being made. What's the appeal? It's not just historical fascination.
But it is a fascination, an attraction of interest. And that interest? Sure, some is historical. And some will claim that vinyl records and vacuum tube amplifiers sound better than digital recordings and transistors. But there is something more. Many youtube videos of old tunes don't need to be 'videos' as such and could be a title card or lyrics, but show the phonograph. And that, for me, is a hint. You can see it working, and with only a little knowledge have an idea of how it works. Vibrations made a needle move, that made grooves in a disk (or cylinder) and now a copy of that disk is making a needle move and reproducing the vibrations. It's 19th century technology at its core. A similar idea with movies, at least on film. There are frames. Photos. Rapidly sequenced. And a flip-book can do something close enough to give an "Oh, I get it." feeling.
Tape is more complicated, but you see a medium moving and have encountered magnets, so there is or can be an idea of how it works. Granted, records and (reel to reel) tape might just fun to watch in certain moods or states of mind. For tubes, well, it's not nearly as easy, but it's the idea that this collection of relatively small number of discrete parts is doing that, that you at least have a chance of understanding it.
Compare the modern mp3 player (which for many is now a subset of all the functions of their phones). It's a literal 'black box' that sound comes out of. Other than earphone diaphragms and perhaps pushbuttons there are no moving parts. It might as well be magic, even for those who do have a good idea of how it all works. It's nice, yes, but there might be this vague unease of, well, what else is going on? I wonder how much of the nutty conspiracy type nonsense is fueled or enabled by the unease of being surround by things one doesn't necessarily understand.
The 'magic' is wonderful and modern life wouldn't be modern life without it, but the older technology is comfortable and comforting in a way. To use the terms of Harry Potter, we enjoy having the powers of wizards, but are nervous that overall, we are really muggles.