In the lifespan of the human species, horses are a relatively new thing. We only domesticated them between 4000 and 2000 BCE in Kazakhstan.
i bet people have been trying to ride every big animal just for shits and giggles since there have been people. because that’s just the kind of dumb thing people do. so a few millennia ago on the asian steppe, which is a boring place with not much to do, probably some people with no hobbies, who maybe were not having much sex and not good at crafts, got really into riding on horses. for the same reason that people get into frisbee golf or pole dancing: they’ve got energy to burn and it’s fun.
and then it turned out to be kind of not that weird after all and actually pretty useful, so it stopped being a goofy passtime and became a practical part of daily life.
that’s my theory.
imo, archaeologists and historians vastly underestimate the amount of innovation that results from people being young, hyperactive, and bored.
imagine young humans jumping on random animals for like a hundred thousand years of shits and giggles until all of a sudden we jump on one that’s like ‘hey…. this is pretty alright!’ and then we had horses
just moving along like everyone else 