In the beginning…
There was no separate division for amateurs. They had to show against the professionals in the open divisions.
So the origin of the amateur division was for the ladies who lunch to have a better chance to win ribbons by competing against each other, not against their trainers. So the amateur rule was written to prevent people from being amateurs if they earned money from riding or training horses. It had nothing to do with ability.
They were not necessarily people who had jobs, so the concept of an amateur who worked for a living and did not have all day to ride and show was probably not factored into the equation for some time.
I think the adult division came about later for the people who could not afford to buy a 3’6” horse, but still could buy or lease a horse to show at the 3’ level.
And then the same same thing happened again. The good 3’ horses got so expensive that there was a demand for a division at a lower height, so more people could participate, even if they were not millionaires.
That’s my impression, anyway.
