“How many middle-class families with children do you see being raised in the West Village today?” asked Christopher Klemek, a 33-year-old assistant professor of history, sitting at a table outside the White Horse Tavern on Hudson Street late last week.

Mr. Klemek has been pondering the question over the past several months as he put together an exhibition on Jane Jacobs, the onetime Village resident who became an urban prophet simply by gazing out her window a few doors away from the tavern. Actually, the question does not take much to ponder. Just use Jacobs’ primary method of research: look around.

“When Jacobs was here, this was a neighborhood which included old working-class tenants from old immigrant stock, new immigrant groups, particularly Puerto Ricans who were just coming into New York in large numbers, middle-class families like her own, some affluent residents, as well as bohemian counter-cultural figures,” Mr. Klemek continued. “This is not a neighborhood that can support that broad swath of social diversity any longer. There are a few people grandfathered in there with rent control, but not new arrivals.”

In 1961, Jacobs penned one of the most famous passages in urban planning literature—maybe the only famous passage—by describing the “ballet” on that stretch of Hudson Street. Merchants swept the sidewalk in front of their stores; teenagers dropped candy wrappers as they walked by; and longshoremen dropped by the White Horse for a pint.

Now, it’s as if the packaging is the same but someone switched the contents—or maybe it’s the other way around. The small and modest buildings are, thanks to a historic district designation, not only small and modest but also twee and quaint. There are still a lot of people on the street and there are still a lot of independently owned stores.

But the teenagers are largely absent, as are the longshoremen. The deli and the hardware store passed away; the laundromat has either disappeared or turned into a dry cleaner. In the building where Jacobs, a journalist, once lived with her family is a children’s clothing store where T-shirts with a picture of the Statue of Liberty playing the guitar sell for $36. At the corner stands a Portuguese restaurant that serves “organic beef filet mignon stone-grilled at the table” for $32—which, given the trouble they seem to go through to make it, actually sounds like a bargain. The White Horse is just about the only place that has remained the same.

If Jacobs’ point was that normal unglamorous neighborhoods like hers turned out to function quite well and did not need any urban renewal, she turned out to be right. The West Village has functioned so well that, 46 years later, it has become quite abnormal and fairly glamorous—and very expensive.

This paradox is one of the themes that the exhibit “Jane Jacobs and the Future of New York,” which Mr. Klemek curated, will explore when it opens Sept. 25 at the Municipal Art Society, 457 Madison Avenue at 51st Street. The show, which lasts until Jan. 5, includes an evaluation of different neighborhoods around the city according to the criteria that Jacobs laid out for successful communities.

Bay Ridge, Brooklyn, and Astoria, Queens, come out looking pretty good, Mr. Klemek said: “Diverse people on the street at diverse times for diverse reasons.” The West Village, by contrast, is just too gentrified—or, as Jacobs, who died last year at age 89, would have called it, “oversuccessful.”

“The loss of that particular element—the affordability of buildings and the variety of conditions—can really change a place radically, just as radically as the wrecking ball might have,” Mr. Klemek said.

Mr. Klemek, an Upper West Side resident who commutes to teach at George Washington University in Washington, D.C., once a week, suspects that Jacobs herself may have been part of the early gentrification trend. But she was, at the same time, immensely concerned about keeping her neighborhood diverse. After her community group defeated an urban renewal plan that would have torn down part of the neighborhood, it turned its attention to building affordable housing, a project that eventually became, many years later, the West Village Houses on Washington Street.

But the degree to which Jacobs would have lamented the undilapidated condition into which the West Village has fallen is a matter of some dispute.

“Jane did not see the Village as being gentrified in a negative way,” said Roberta Brandes Gratz, a writer and social critic who founded the Center for the Living City at Purchase College with input from Jacobs. “Obviously, the businesses changed, but she never expected things not to change; but the essential character of the place she celebrated—the fabric, the feel, the diversity of the street life—are very much in keeping with what they were when she was writing about it.”

In April 2004, on her last book tour before her death, Jacobs dropped by the neighborhood once again to speak at a meeting called by the West Village Houses Tenants’ Association. Afterward, according to Ms. Gratz, who accompanied her to dinner that night, Jacobs was energized by the civic spirit she saw on display.

“I just remember her being exhilarated by the continued commitment and energy of the local citizenry, and she always felt that that would be what every community needs to sustain itself,” Ms. Gratz recalled. “She was just as cheerful as could be.”