Another tiresome ‘back in the day’ story
… back when dinosaurs grazed alongside the horses … everyone who jumped for more than a year or so was jumping 3’6". That wasn’t “high”. It wasn’t nothing, either. But any reasonably competent rider would get there. We were not geniuses, we weren’t headed to big shows.
The lowest class entry, the beginner jumpers, was 2’6". Of course people started over their first jumps at lower heights, but quickly worked up to a standard 2’6".
We also rode our horses across huge tracts of natural open land, thousands of acres. That wasn’t weird, it was just a Saturday. We had jumping courses that had solid ‘natural’ jumps that I now know are eventing cross-country – we called it ‘field hunter’. We went on group rides over long distances, along roadsides and across open land. Oh, and, everyone who rode did so at least twice a week, three times was common. And so on.
From beginner status on, we saw these things happening all around us, had examples to emulate of riders not much older. This context was part of the natural progression of learning riding, if you continued to ride and gain skills. It was customary, usual, normal.
In the U.S. there has been a gigantic change in riding culture for jumping. And other things. Riders who are afraid to leave the ring other than to walk to another ring. Riders who haven’t seen anyone jumping more than an 18" crossrail, who think that an 18" straight horizontal bar is a big ask. And so on.
Big factors seem to include the suburbanization of former rural locations, the lack of exposure to any farms or animals other than a riding school, as well as the demands on everyone’s time that limits the participation of many people to one hour a week in a very structured setting. So many riders never experience the context of higher levels of riding and expectations. So it isn’t in their expectations.