I'd like to note here that the lifespan of a horse is 25-30 years. They were phased out not with mass horse genocide, but likely in the same way we phase out Toyota Corollas that have gotten too old. Owners simply didn't buy a new horse when the old one wore out, but bought an automobile instead.

Economically it is no different from the demand for Mitsubishi's decreasing except the vehicle in this case eats grass, poops, and feels pain.

If you want to analogize with humans, a gradual reduction in breeding (which is happening anyways with or without AI) is probably a stronger analogy than a Skynet extinction scenario.

Truth is this is no different than the societal trends that were introduced with industrialization, simply accelerated on a massive scale.

The threshold for getting wealth through education is bumping up against our natural human breeding timeline, delaying childbirth past natural optimal human fertility ages in the developed world. The amount of education needed to achieve certain types of wealth will move into the decades causing even more strain on fertility metrics. Some people will decide to have more kids and live off purely off whatever limited wellfare the oligarchs in charge decide is acceptable. Others will delay having children far past natural human fertility timespans or forgo having children at all.