I think this might be true for some... but I think there will always be beer geeks who find making it just as fun as drinking it, if not more so.
That would be me.
OT warning: OT coming
THIS I think is a huge one.... it's the same thing that is affecting a lot of things... Think about Fraternal organizations like the Moose, or Masons, etc... they've gone down a slippery downhill slide in terms memberships over the last 2 decades.... And I think even Veteran Organizations are suffering in the same way- even though there's always vets, newer generations of people aren't big on joining "clubs" that much these days.
I'm thinking we're becoming a less "active" society? Though I thought that over the last few years we've had a peak in DIY culture.... think Maker's Fairs, etc. I thought everything like this was peaking...
I can't let this go without adding a comment. Why are people less involved today? My view is that in times past, there were simply fewer things competing for people's time....and there are more ways to connect to people than there used to be.
Take this forum as an example. I get to have discussions with other like-minded people here that would be impossible without the internet. There just aren't very many people locally doing this beermaking thing, to say nothing of doing it at the level I am doing it. The only place to find people, knowledgeable and imaginative people, is on the web.
Same goes with things like Facebook and other social media platforms; in some ways, they replace the need/desire for face-to-face interaction. People used to connect with each other at gatherings, and that was largely the only way they could easily connect. Now, I'm engaging in conversations with people across the globe, and have less need to interact in face-to-face environments.
The same thing goes for entertainment. At a time 125 years ago, how could you hear good music and song? It had to be played and sung live. What about drama? Had to be done live. Much of what people did for entertainment required personal interaction and connections at gatherings often held explicitly for the purpose of entertainment. Not any more.
We are no longer geographically limited in our associations. My local homebrew club isn't local; it meets 25 miles down the road in Dubuque. I have one local brewing friend; the rest are online or in Dubuque. Most brewers in that LHBC are extract brewers; few can engage me in a conversation about all-grain, to say nothing of the effect of PH on finished beer flavor (a discussion I'm having with Morrey via email right now). They don't read HBT, don't read Brulosophy and the exbeeriments, don't buy the books I do. The only place I can find people to engage on these topics is HERE.
Whereas once people might be limited to joining just a few local organizations, now the menu has expanded drastically. It's one reason why, locally, our community theatre struggles. Back in the day, it's what there was. Now, it has to compete with Netflix, cable TV, Dish, etc. And it can't do it.
It isn't so much that people are less active, I don't think, as they are less active locally. But often still, they are active.
My 2 cents.