Road/car dominance wasn’t exactly established in a free market either.
There’s a whole host of subsidies for building/maintaining roads paid for by everyone [1]. There’s the regulatory advantages driving has (ex: the common zoning requirement that new construction ensure enough parking space [2]). There’s the negative externalities of highways/roadways. (Ex: the health impacts of pollution[3], and the health impacts of sitting in a car rather than walking/biking (part of the way) to their destination [4])