The Downtown Brooklyn Partnership, which manages the neighborhood’s three business improvement districts, said that the demographics of the block had essentially not shifted and that the new stores are just as popular with the street’s traditional customers.

“Retailers are going where the shoppers are,” Tucker Reed, the partnership’s president, said. “They’re not making decisions based on the color of the shoppers’ skin, but by where there’s demand for a product.”

Marty Markowitz, the departing borough president, said the new chains were returning the street to its peak mid-20th century years, when it had half a dozen department stores like Abraham & Straus and Mays that catered to both Brooklyn’s more affluent residents and those looking to stretch a dollar.

“H&M is the first wave of the diverse shopping experience of Fulton Street,” he said. “When I was a boy, there were opportunities at every income level. My mom used to drag me to Mays at the lower end and A&S at the upper end.”

Mr. Shapiro said that recent development had already pushed out more than 100 smaller businesses that provided a solid livelihood for merchants, an option for lower-income shoppers and hundreds of jobs to young strivers.

“For people of color, it’s been such a successful economic model,” he said.

Fulton Street has been Brooklyn’s marketplace since the early 19th century. At its peak it had half a dozen department stores, but in the 1970s and 1980s, it became somewhat raffish, the scene of news-making robberies and shootings. Still, it drew working-class families shopping for shoes, televisions and clothing.