I’m very much anti-car. I don’t own a car. My apartment doesn’t have a car park (at my request before it was built). … But I think you’re really over-egging the utility of horses. I don’t think they are anywhere near as viable in dense urban environments. I’d say a bicycle is far more realistic alternative to a car (I say that from experience). Perhaps an electric bike depending on your needs.

Keeping a horse takes a huge amount of space and resources. Perhaps you can do that if you live in a rural area and own a bit of farmland; but otherwise, I don’t think its is affordable or practical to own horse.