Emissions, mileage, crash safety standards in the USA punish smaller more fuel efficient cars. The larger the wheel base or "shadow" of the vehicle the easier for it is to meet Federal standards.
This is why nobody sells small pickup trucks here. It is a lot easier for Ford to produce F150s that get 25-30ish mpg then it is to produce small trucks that get 40-50.
The Maverick is the only exception and it isn't really that small and it is also a hybrid.
Essentially the Federal government made selling small cheap cars infeasible in this country.
Also because vehicles last a lot longer thrifty Americans avoid buying new vehicles. They would rather buy a used one and let somebody else absorb the depreciation hit.
And when buying a used car most people are going to want a used mid-ranger or higher end car then buying a used economy car.