Second, I don't think there's a revolution for the general population. Your archetypal middle-aged dad / curious teenager are DIYing less than 20 years ago, which in turn was less than 40 years ago. The stats here are clear, most of "garage" occupations are on the decline. Less space, higher costs, more emphasis on safety. Some hobbies, such as backyard chemistry, are effectively gone. Shop classes in most schools are gone. Making your own bookshelf or building a radio from a kit is no longer a rite of passage.

Third, the "explosion of niche products" - maybe, but I think some of it is just visibility. Kickstarter, HN, Hack-a-Day, and so on. Before that, we had hobby journals for woodworking, electronics, etc, and they were always full of ads for niche gear. You just weren't seeing the totality of it in a doom-scroll loop. Visibility has benefits, but my point is that the qualitative change isn't as profound.