But a car or some other form of stable four-wheeled transport that can move them from door to door is necessary for a disabled person’s mobility

Which disabled person? Disabled people are not a monolith, and many are unable to drive but perfectly capable of riding a bike, adaptive or otherwise.

Disabled people and poor people are both disproportionately negatively affected by automobiles. The idea that they "have" to have access to a car because they are disabled isn't proof that disability requires cars, it's proof that even the people who can least afford it are burdened with having to have a car.