Interestingly, the recent proliferation of chain fast-food restaurants and retail outlets in South-Central LA is actually the solution to an older problem.
As you'll recall, South Central LA witnessed vicious racial pogroms in April 1992 against immigrant (typically Korean) entrepreneurs operating within the black community. Korean shopkeepers tended to treat black customers brusquely and would seldom hire and almost never promote local blacks.
Since then, corporate America, often in partnership with black entrepreneurs like Magic Johnson, has greatly expanded the number of chain outlets in South Central. These are more willing to employ local residents than immigrant mom-and-pop establishments, and promote them too.
For example, the Florence-Normandie neighborhood where the 1992 riot broke out now has a quite decent chain-run supermarket with a first rate fresh produce section.
In general, the Stuff White People Like coterie sees immigrant-dominated retail streets as "vibrant" and chain-dominated retail streets as "boring," but the latter are better for African-Americans looking for jobs.
On the other hand, Hispanics are slowly pushing blacks out of South Central, so a lot of businesses tip to all Hispanic. Once you reach a certain percentage of Spanish-only employees, you have practical reasons to start demanding that new employees all speak at least Spanish. And there are virtually no bilingual African-Americans in LA. (Among the 900 black LAPD officers, I was told on good authority in 2001 that only four spoke Spanish—and LA cops have plenty of reason to learn Spanish.)
By the way, the ban on fast food restaurants is hardly unprecedented. It's just that they are usually banned in upscale neighborhoods. For example, Avalon, the quaint little tourist town on Catalina Island, had, as of my last visit in 1997, absolutely no national chain restaurants, retailers, or hotels of any kind. Similarly, on Martha's Vineyard, McDonalds famously waged an epic battle trying to get permission to open an outlet.