People will figure out a way to make personal transportation happen. Count on it.
We can make oil from coal.
We can come up with better electric cars, and build more nuclear generating plants.
And that’s just for starters, with pretty well developed technologies. Algae-based biofuel is one that’s on the horizon (burning corn is a lousy idea). There are others.
We aren’t going back to walking and horses.
No, not horses. That would be stupid. But we might end up with partially enclosed three wheeled mopeds or something like that.