My ill-informed and random thoughts on this topic:
At least around here, I don't see homebrewing in much (if any) of a decline; the crowds at my now-former LHBS are anecdotal testimony to that.
In the past, a few people I know wanted to see how beer was made at home, so I'd have them over for a brewday, so they could see my process and decide for themselves.
Same outcome every. damned. time: They enjoyed standing around, drinking my beer, playing on their phones, and not really paying any attention to the brewing process, or if they did see what I was doing, they'd later decide it was too much work vs. just buying it at the store.
I see that as just another temporary ebb in the hobby, not too unlike the craft beer industry as a whole: those in it for the long-term, who know what they're doing, making good beer, and in the case of a brewery, making sound business decisions, will stand the test of time.
The rest will fall by the wayside.