For a different perspective, it's the difference between the kind of (pro-innovation) restrictions imposed on automobile companies versus those (anti-innovation) ones imposed on aircraft companies:
1. For some reason it only talks in terms of the USA, there's a whole world of manufacturers that could have stepped up to create flying cars if the market was interested.
2. There was, for a very long time, a thing called a "microlight" which allowed people to own their own snap private air craft (although not generally VTOL)
https://fee.org/articles/how-the-faa-is-keeping-flying-cars-...