I think your observations are more a commentary on society at large than on just the audio(phile) hobby...
I have a few other long-time hobbies I still enjoy (saltwater reef aquariums; road cycling, for examples) and I have seen the same trend in those hobbies as well.
People just do not put as much value or effort into in-person socializing as they used to. My opinion is the 'blame' for that lies in the increasingly large role that online services play in our lives; coupled with a generally more self-centered attitude that people tend to have today. I think the whole Covid shutdown thing served as a final "nail in the coffin" in some cases, but I had seen this trend long before Covid.
Per my personal examples, our local Reef Aquarium Hobby Club started in 1995 and for 20-ish years we had a monthly public meeting that would draw sometimes hundreds of hobbyists (depending on that month's activity)... starting about 2016 attendance, participation, and paying memberships began to decline. By 2020 we cut back meetings to quarterly due to poor attendance and declining revenue. Our last event was in 2024... today the Club is basically defunct. Even the national Reefkeeping hobby group (MACNA) went belly-up in 2025 due to lack of interest in attending the annual 3-day conference. 5 - 10 years ago, that conference would draw 7 - 10,000+ PAID ticketholders to various Convention Centers throughout the country...
Even the cycling world has seen changes. Formal cycling groups have either dwindled down to 10% of their former participants or outright folded... I can't even get more than 3 or 4 people to commit to even informal "let's meet at X on Saturday morning and ride to Y together..." anymore - even with months of advance notice. People just don't care to socialize as much as they used to. And younger people particularly are actually losing the ability altogether; to the point that they will avoid many public activities... even things like grocery shopping or eating out (hence all the shopping and food delivery apps)...
Kind of sad, really. But definitely beyond the scope of just this one hobby.