You do both incrementally and simultaneously. Yes, this is a terrible idea in the middle of exurban sprawl. Don’t build them there.
The people most likely to move into these buildings are the people best served by existing transit. If you’re able to bike, train or bus to work, you’re more likely to get one of those units than if you drive 120 miles to work.
A number of cities already have decent to ok transit networks. So you make it so expansions to those networks result in transit-oriented development, and upzone existing walksheds of your transit to transform them into pleasant walkable mixed-use areas if they aren’t already. You improve things over time and people who prefer walkable, bikeable urbanism will move in.