Not sure about horse and buggy. Not sure about how most people would feed/store them? But do tell.
Bicycles are ok but limited. Everyone wants to drive huge cars. That's great but it makes it very unsafe for smaller and more fragile cars to drive with reasonable safety. The basic fact is when you are moving around something that weighs 20x what you weigh just to get somewhere - there is a huge inefficiency.
The real solution is mass transportation but we're too busy fixing every highway in existence for more traffic. This shit takes 10 years to plan/complete it seems and by then we're going to see more and more effects and have to start abandoning that approach. Rebuilding infrastructure won't be cheap and understandably leads to resistance to these things.
Again, I'm not saying what we should do, I'm just stating what would need to be done. And don't forget nuclear. This is where the greenies are wrong.