I'm not aware of the chemical hobby era. And as I watched it happen, the electronic hobby era died at the same time as the mechanical. Most of the mechanical one was cars. It happened as it became harder to repair things. The barrier to entry increased, the availability of parts decreased with decreasing demand. It is a negative feedback loop.

Mechanical: I was thinking more Meccano and home built steam engines - cars came later.

Chemical: I was thinking chemistry sets and the age when Chemistry was geeky cool (Du Pont, Uncle Tungsten).

My grand father was a structural engineer, my father studied chemical engineering, I studied electronic engineering (but got a job programming). So perhaps I was thinking more of the frontier of engineering shifting rather than technical hobbies.

It would be interesting to look at geeky hobby adverts in a magazine over time and see how the advert focus shifted.

  > I was thinking chemistry sets

I don't think those chemistry sets were ever widely popular. We see them and look back thinking how cool and dangerous, but every one I'm aware of was insanely expensive. Same with the atomic kit.

On the other hand, most mechanical things were relatively cheap. Cars were worked on since cars existed. People also worked on everything in their homes. There was the tradesman who takes a specific skill like being able to fix a washing machine, but a lot of these people had hobbies of building and making.

So we have a direct connection to the death of the repairman and death of the handyman. These were quite popular things even up through the 90's. You'll even see this in shows and movies.

Plus, you forgot the most popular hobby of them all: woodworking. Still alive, but nowhere near as popular as a few decades ago.

Yeah, totally—once fixing stuff got harder and parts disappeared, the whole scene just kind of faded out.

> Most of the mechanical one was cars. It happened as it became harder to repair things.

I don't think it has become harder to repair cars though. Most problems that need repair are the same old bushings, brakes, spindles, rust, bearings ...

I think it is some cultural change away from handy work in general.

Electronics have become harder to repair with smaller and more integrated circuits though.

Seems to me it's integration of whole systems.

Doomscrolling and influencing.

Telling AI to write computer software.

Mechanical.

Circle of life. ;-)

It is not just a question of popularity. Post 9/11 skillsets around chemical ( or other scary looking domains ) became vilified within general populace and then that vilification was normalized with shows like 24 ( which is a great show... it just sucks that people are unable to separate the world it presents from their world ). It does not help with the advent of red flag laws, where neighbors can effectively call cops on you if they see something that bothers them..