I think it takes the general populace saying , "we don't like the look of that bizarre, unreal gait. It's ugly and false and demonstrates real vanity and selfishness if , for show, a human puts animal in such pain, and for what? So that you see a gait that is so utterly unnatural? It's a bit like the old corsets that women wore , with bussles on their butts to give a very unnatural hourglass shape. It caused a lot of health issues for the women, all for show. The horses have no choice. But as long as this is valued by the audience and paid for by the horse buyer/shower, it will persist.