They probably invented ladders, too.
Makes sense.
The Steppes were far enough away from the “civilized” center of gravity that declared riding horses undignified for royalty, and royalty being the only people of enough means to own and maintain horses.
And the distances to be traveled so great and the “amenities” along those travels so scarce that anything that sped up travel was a serious boon, in the Steppes.
They probably invented ladders, too.
