This hybrid approach still requires purchase and regular operation of an entire personal vehicle, which will not be entirely attenuated by simply driving half a

This hybrid approach still requires purchase and regular operation of an entire personal vehicle, which will not be entirely attenuated by simply driving half as many miles. So if [driving] and [public transit] both cost x, the hybrid solution will definitely cost more than x, up to 2x, which means most people will only do one or the other.