Just to expand on my answer.
I think, as RobinL indicated, the overriding factor for the vinyl revival has to do with the physical factors, the form factor, aesthetics, tangibility, nostalgia for some, turntables being kinda cool, and the way the physical LP medium affects how many feel and interact with music.
First to your point: I don't see anything to suggest that modern music sounds better on LP. There may be some preferences that way, but I think that would still be niche given the majority of the population are quite happy with digital streaming. As to the dynamic range differences, there's some controversy over that, but ultimately that is more audiophile nerd concerns. The vinyl revival is WAY bigger than the audiophile nerd market, it's gone pretty mainstream, and I'd think the vast majority of people buying vinyl (a lot being Taylor swift fans!) have no inkling about the issue. Most people aren't thinking "there's not enough dynamic range coming through Spotify!"
As for the sound, I think it trails those factors, but it is still a significant factor in a way. It's very clear that "the sound of vinyl" is often a subject that articles and many vinyl enthusiasts talk about. But it's a big mishmash of issues. Some vinyl fans just accept the claim without thinking about it much. The fact is vinyl does tend to sound different, to one degree or another depending on everything from the mastering, pressing, and all the variability in the user end of turntable/cartridges/set up etc. And then of course there are the vinyl artifacts of noise, pops, ticks
So there is often going to be a real sonic difference to notice. And the reactions there are varied: some notice and think it sounds "better" than what they are used to however they listen to their digital sources. Some think it sounds worse, but will put up with it because they enjoy the other aspects, they don't even care that it sounds worse. Some think it sounds worse, but they say they LIKE it...I've seen quite a few vinyl enthusiasts, almost always newbies/young people, who say they love the ticks and pops and distortion! Then there are some who hear a difference but don't care. And then you have some who declare they often prefer the sound of vinyl.
So I do think "the sound of vinyl" is a pretty wide-spread element associated with the revival, but it's a big mish-mash of attitudes, biases, etc. But since you can find people on all sides of the issue about the sonics, yet almost ALL of them will agree the physical aspects of the medium is hugely important, I'd put the physical aspects as the main common denominator in the revival.