While humans can run very fast, we excel not at speed but endurance. We can outrun every land animal including horses. The primary hunting tactic of humans, other than ambush and traps, is to chase animals to exhaustion including horses. Several tribes around the world still hunt this way.
But yeah, horses are disproportionately faster to humans than they should be, if it were real life. In game the horses are always running at a sprint but people are barely even jogging. If there was a toggle-able sprint mechanic in game for characters? Sure then we could compare the sprint speeds.
I don't like this thread already, so much misunderstanding of top speed and endurance of humans and animals
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. The game is far from real life and won't be like real life.