Futurology

The horses didn’t have a population explosion and lack of resources due to their work being gone, on the contrary, their numbers dwindled – which is not a bad thing, as long as it is through natural means, which it was

Afaik this is not really true; there was a mass slaughter of horses to process them into meat, glue etc. when the potential economic value of most of them fell below their upkeep costs.

Which isn't necessarily to say that the outcome of AI rapidly rendering the majority of humans unemployable will be cannibalism, but I think the implications of this analogy are way more grim than you are letting on. The market does not want to provide for animals or people it can't use. If the same thing that happened with horses is going to happen to us, that is an existential threat for most people alive today, even if it isn't a threat of outright extinction.