Like the OP, I've no hard evidence to share. But going by strictly anecdotal evidence and my own perception of things? There seems to be a small but noticeable interest among Millennials and older Zoomers for pipes and pipe tobacco. But does that mean anything? Fedoras came back in vogue briefly in the early 2000s and were just as quickly ousted out of vogue when they became associated (perhaps somewhat unfairly) with misogynistic dudebros. (To this day, "fedorabro" is a epithet used online, even though the fedora fad has largely fizzled out.) So, is this a real thing with meaning? Or another fad being glommed onto due to its seemingly anachronistic aesthetic?
I'd say it's a mix of both. The cigar shops I frequent are showing an increase in pipe smokers and are selling more pipe tobacco products. That's definitely a good thing, and it makes sense; a person interested in cigars would naturally want to try other premium tobacco products. These shops are typically filled with your older Gen Xers and Boomers, but I'm seeing a lot of people my age (older Millennial) also frequent them, and doing so with full investment into pipes and cigars both. Such people, and I count myself among them, are likely in it for the long haul. And again, this is strictly my perception here, but we are a rather homogenized lot: a lot college-educated white men that occupy the lower-middle to middle classes. Nothing wrong with that! Just something I notice.
On the other end of spectrum are those who are clearly glomming on to a fad solely for its aesthetic qualities. Nothing wrong with that, either! Let people enjoy things, I say. But these people don't strike me as ones that are going to be in this for the long haul. There's a big explosion right now in the men's fashion and self-care industries that are purposely selling the idea of a kind of, ahem, let's say "antique masculinity." These products tap into the collective disappointment many younger men have with the disposability of consumer culture, and also taps into their desire to express their masculinity in a way that resonates with them. Well, right now, popular media is replete with images of vikings and tough-guy early 20th century gangsters in bespoke suits and tweedy caps. So, pipes are just another extension of that kind.