Indeed, there is a positive feedback loop that I choose to grocery shop at a grocer with parking (and the grocer chooses to provide parking in order to get customers) and I choose to drive to my office rather than commute by public transit due to the horrible time inefficiency of the MBTA "solution" to getting me there:
https://news.ycombinator.com/item?id=31723197I almost never want to go to the city center (in part because it's still a pain in the ass and time-consuming to get there, due to needing to use a bus and a subway or possibly a bus and two subway lines). I can find ready substitutes for most things in the mid-density half-urban area near where I live or in one of the nearby suburbs which are terribly connected by public transit [buses only and mostly radial bus lines].
If there was excellent public transit, I agree there'd be more services highly coupled to the transit hubs. As it is, much of the shopping areas have vast parking lots/garages instead, because that's how the merchants can stay in business: by catering to people who can actually get there efficiently.