alt Hacker NewsI think it's most obvious in hindsight, probably it was a long time (some decades) before cars were understood to have much of a negative effect at all. Nobody* thought much about air pollution (even adding lead to the gasoline) or climate effects, or what would happen when cities were built enough that they were then dependent on cars, or what happens when gas or cars gets expensive.
All they saw was that trips taking a day could now be done in an hour and produced no manure, and that meant suddenly you could reasonably go to many more places. What's not to like? A model T was cheap, and you didn't even need to worry about insurance or having a driver's license. Surely nobody would drive so carelessly as to crash.
*well, not technically nobody, but nobody important.
If you read the period news, pretty much everything except lead poisoning and climate change was well known by the 1920s. Rich people wanted cars but a ton of places had resistance from everyone else to what they correctly recognized as removing the public spaces they used and shifting externalities to, for example, the people being hit by cars.
What’s really interesting is that you can find newspaper columns in the 1920s recognizing what we now call induced demand as even by then it was clear that adding road capacity simply inspired more people to drive.