We see the same with dinghy sailing. It used to be a big scene with hundreds of ordinary people showing up for regattas. It was killed by windsurfing (at least here in Europe) and just people moving on to other things ,not regulation of any sort.
People have plenty of expensive and time consuming hobbies. All hobbies are at least time-consuming, that's what a hobby is.
All certifications add to the expenses. It's the reason why one can't buy a headset off amazon and have to pay 1k for a used headset. Sure, safety requires certifications but I guess we went overboard. It's also the reason why GA aircraft are expensive to this day, even those build 40 years ago. It's pretty expensive to keep maintaining old tech at low volumes. I'm rooting for Diamond and their car-derived engines (as well as the Experimental aircraft scene).
Note that boats are also notoriously expensive.
There's a very good parallel to your example: gliders. You want to fly cheap (just to fly, not to go places)? Go soaring. Problem is, it's even more location-dependent.
Why is this worse than the 80s?