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.