Unless we are talking about improved fidelity, transparency, in the Sheffield sense, "Better" is a subjective evaluation depending on how something appeals to one's tastes. Tastes that are informed by listening to the coloration and artifacts of the gear used to make the music we grew up on.
Originally, the electric guitar was invented to try and make an acoustic guitar louder. But it didn't sound much like an acoustic. And over the years, the louder folks turned it up, the further away from an acoustic guitar it sounded. Now, most folks are accustomed to the sound of a Les Paul into a tube amp. And although a Parker Fly into a Line 6 Spyder is probably higher fidelity and more accurate, the Les Paul is the sound of rock and roll (unless you're a Fender person) and the "warmth" and other colorations are what sound "right" to most people.
If you asked a guitar player in 67 whether a Gibson 335 sounded better than a Harmony Meteor, the answer would be an unequivocal "of course". But now we have this reverse vintage lust where some kid who's seen a picture of some old blues guy playing a Kay or Harmony, and is trying to reproduce that sound in order to be authentic, will say the Harmony sounds "better".
Same thing happens with audio gear. How many posts have talked about all the great hits that were made on SSL desks? When those desks came out, experienced engineers cried to get that thing with the computer in it away from me, it sounds horrible. But cost efficiency won out and the speed of workflow triumphed over sound quality. And so you have a sound imprinted on folks over a couple of decades. The sonic signature of their favorite songs.
Although at heart I'm a musician who believes that tone is in the heart and fingers. And an audiophile who wants to hear though all the gear to the truest conveyance of those hearts and fingers. I recognize that most recording is an illusion to create an esthetically pleasing event. Realism is secondary. The emotional impact of production over just presenting the musicians as they are. Augmenting them if you will.
And so technology marches on. And slowly the colorations and artifacts that we grew up disappear. And it sounds wrong. So the retro movement kicks in to try and restore that familiar sound.
In a way it's kind of funny. If you transported a bunch of BBC or Capitol engineers out of the '50s to now and let them read some of these threads, they'd be shaking their heads. Years of fighting with temperamental equipment when you can reliably and repeatably get the effects you want by twisting some encoders on an interface? Absence of all those artifacts they've been trying to work around? Where do I sign up?
It's like when some kid comes up to me proudly showing off his "vintage" Harmony Meteor (which someone did a couple of months ago) and how great it is. Gaaa! I played one in 67. I have a 335 now. I can roll off tones, muff strings and get it to have that choked stuffy sound of the Harmony, or I can get clear rich tones from it that the Harmony could never manage.
It's interesting to look at the bass guitar world. While there is still a fringe of "trad" folks with old Fender Precisions and flat wound strings, the bass world embraced technology and advanced concepts. Creating broader sound capabilities and playability that surpasses what most guitarists could accomplish in the '60s.
Plus la change, plus la meme chose.