Horses are much more expensive to own than cars. You can't just leave them sitting in a lot for 20 out of 24 hours a day, they only feed themselves if you're living out in the middle of the prairie, and you can't just replace a broken leg.
If horses are more "pro-social" than cars, it's because the only people who could afford them are the very wealthy and people who made their living riding horses like cowboys and taxi drivers. Cars are "worse" than horses because they're too superior, which means the middle class all own personal cars and have stopped financing public transit and pedestrian-friendly city layout that the lower classes would coincidentally benefit from.
If horses are more "pro-social" than cars, it's because the only people who could afford them are the very wealthy and people who made their living riding horses like cowboys and taxi drivers. Cars are "worse" than horses because they're too superior, which means the middle class all own personal cars and have stopped financing public transit and pedestrian-friendly city layout that the lower classes would coincidentally benefit from.