I see them out in the hinterlands, munching away on hay or just standing there by the freeway, waving their tails at flies.

Now that we have cars (and bikes) what are they good for?
Unlike cows which obviously serve a purpose, horses don't do anything but just shit or make some rich doofus ride around his spread feeling like he is a cowboy. Even real cowboys, if there are any, use motor vehicles if they want to do their job efficiently and quickly.
My point is- these horses we all see loitering around not doing anything any more? They are pointless.
By the way, if you own a horse, go ahead and respond with what beautiful creatures they are and what an important recreational purpose they serve in your life as you pay for it's housing and feed and shit clean up. It's really important that you have horses. It just is.