The irony being, of course that a true "conservative" that cleaved to the values they claim to care about would absolutely want this kind of car-light/car-free downtown.
Time and time again, complete streets and walkable cities are shown to save huge money on the city budget. They cost so much less to maintain and they boost economic productivity so much. The return on investment is just immense compared to car-intensive infrastructure. There's a reason a city like Houston has something like double the per capita spend on transportation of a city like NYC in spite of NYC's massive subway system and there's a reason NYC has something like double the per capita spend on transportation to Amsterdam with its vast networks of bike paths and trains. Car-intensive infrastructure is crazy expensive to maintain. It's unfrugal madness.
And for the non-financial side, car-intensive civic design still doesn't qualify as "conservative". Having car-intensive design requires a huge, top-down approach to urban planning where the city tries to plan every aspect of its citizens lives. Plan for them and fit them into figurative boxes in order to make the literal boxes practical to use. It's practically authoritarian. It's a violation of the traditional values of cities which grew slowly and organically, adapting to the changing needs of their citizens through work done typically by those very citizens' hands.
Switching urban planning models to a car-first approach led to a lot of the other problems of modern cities, including the fact that small-scale/neighborhood developers have been all but run out of business by huge outsider development firms that refuse to build anything other than huge exurban sub-developments and luxury condos. Conservatives should be there to resist and reject this total upending of normal development of society, but they make money off of it so stay mum.