New concept?  Hardly, New York City allowed it in the late 1940’s:

Many objected to the rich subsidies offered Metropolitan Life, then the largest private corporation in the nation, as well as the firm’s refusal to rent to minorities. Others criticized the complex’s design and layout. Metropolitan Life wouldn’t allow schools, churches, libraries, or other public facilities within the project’s boundaries out of concern that they might attract undesirable elements. Urbanist Lewis Mumford discerned “the architecture of the Police State” in Stuyvesant Town’s dozens of featureless redbrick buildings, arrayed in rows across 80 acres.

Today Christian churches, and especially Evangelical ones, do two things: tout the social values of church and the ethic that goes with it, and contend that, until recent times, everyone else acknowledged it.  The former is certainly so, but the latter has never been a given, and certainly was not in the last century.  Obviously MetLife was more worried about keeping the riff-raff out than edifying the (presumably all-white) residents.

As a Palm Beacher, however, such problems have a solution.  Had MetLife had the likes of Bethesda’s vestry at the time, they certainly could have found a way to have a church within the complex and keep the riff-raff out.  Whether the church would have had much of a Biblical basis is another problem altogether; the vestry showed its ability to mishandle the Word when the situation called for it.