Maybe they were never intended for cars?
Maybe it was a cost savings thing? Homes that are only 50-75 years old seem to have larger carports instead of garages.
* I answered my own questions. A model T was 66 inches wide but had 8 inch running boards on either side so the crew cabin is closer to 50 inches. The doors, if it had them, would be shorter as well. A model S is 77 inches wide so that's probably 24 inches difference in clearance.
1 my car is nice and clean most of the time now
2 no more gas station dirty hands on the gas pump, I'm OCD umk
3 I get to watch my car pull out of the garage every morning in amazement :)
Tesla pushed an update that enabled this as a "convenient" shortcut to the more elaborate, safer method you describe. In fact the video author praises it. Seems like a nice handy feature.. At first. Safety-critical design needs more care than this though.