@whart
To add some evidence to support your hypothesis… ham radio. Back in the 50’s and 60’s there were the adult nerds with huge antennas sticking up from their houses (modest homes). The talked to people all over the world… other ham operators via short wave. It was at the forefront of hobbies… and was really important communications durin WW2. They are gone… come on, any left would have been killed with the internet.
On the other hand, high end audio is about music. Music is about as fundamentally human thing that is non-essential to survival and continuation of the species. This has never been a “popular” pursuit… it probably never will… but I don’t think it will be going away in the next generation or two.