Rail of various sorts fixed the transit problem. If we had abandoned our suburban failed experiment the same time nuclear was built out, I fully believe cars wo

Rail of various sorts fixed the transit problem. If we had abandoned our suburban failed experiment the same time nuclear was built out, I fully believe cars would die a natural death as all the gasoline infrastructure would cease to be profitable. So basically it is a combination of no nuclear power + severe restrictions on density (zoning most famously, but also two-track building codes) that prevented this "natural solution". I put nuclear first because it is much more global, while the problems of suburbs + NIMBYism is most pronounced in American. (Still a problem elsewhere but never quite as bad.)