It’s NOT an easy fix. The logistics of that, with the business model as it currently is, are a nightmare. This isn’t dressage where you’re committed to a class ahead of time so they can make a ride order and stick to it - for the vast majority of competitors at H/J shows, they can add same day. The only classes that don’t have that flexibility are the bigger money classes with a set order. It’s not as simple as saying “well, change the business model” - it’s easy to say that, it’s much harder to enact a sweeping cultural paradigm shift. Converting everything to an FEI-style level of oversight is just not realistic, sorry.
What might be more realistic is establishing a national baseline number of shows to count for points, with any additional shows attended after that not counting. Even that, though, gets tricky because what if someone is trying to qualify for Indoors or something, goes to their last show, squeaks in off the waitlist, and then is champion at Harrisburg but now the points don’t count? etc.
I don’t think the powers that be much care about the issue, tbqh, they care about making USHJA money. But I also don’t really think there are scores and scores of grossly lame horses at every show (and I say this having posted previously griping about lameness I watched on live streams, lol) nor that OP is the One True Lameness Spotter. A realistic solution is going to be a lot more incremental than a Big Radical Change.
(and before OP goes after me, I have plenty of experience in the hunter world and on the jumper side, managed a horse at the GP level for the better part of a decade who was still showing at that level when she was 20, so I’m no wet-behind-the-ears naive turnip )