The more equality or perception of it there is, the less likely for huge groups to form a single mindedness. During the 1960s there were not nearly as many black millionaires or any black billionaires. No one imagined a black man would be elected president or someone like Oprah Winfrey who owns her own TV network.
Today there are also black CEOs of Fortune 500 companies. John W. Thompson (Chairman of Microsoft), Kenneth C. Frazier (CEO of Merk & Co.), Ursula M. Burns (CEO of Xerox), and Kenneth I. Chenault (Chairman & CEO of American Express)
The more progress there is the less anger there is.
A lot more blacks believe they can succeed in America!
Although racism is likely here to stay only a fool would believe things haven't improved in the U.S. since the days of Jim Crow and turbulent 60s.
Several years ago when the Iraq War started someone asked why we didn't see constant protest in the streets the way it was during the Vietnam War. The 9/11 attacks and fears of terrorism reduced the number of pacifist.
However I think the lack of a "draft" had the most bearing. There has not been a draft in many years. Therefore anyone in the military today is someone who chose to join.
The protest in the 60s were about being forced to do something against one's will or being denied to participate.
Having choices and experiencing a taste of success appeases most people. Nothing unites people like anger.