Today the pace of change is bracing, as is the insolence of the newcomers. A local real-estate speculator who specializes in flipping buildings in the shrinking Little Senegal section of Harlem told me that new tenants complained, “We’re not paying that much money to have black people living in our building!”

That’s what happens in the rentals, he said. But, he added, “What really upsets them is having blacks freeloading in noneviction co-op conversions. Blacks are paying $800 a month for the same four-bedroom, two-bath unit the newcomers bought for $2 million. Whites pay $2,000 just for maintenance! It’s not the blacks, but their poverty that’s resented. They ask me, ‘How come they didn’t buy this building when it cost nothing?’ ”

These are just some of the myths newcomers like to tell themselves, that gentrification isn’t about race, but about wealth and social class. But especially in Harlem, is this not a distinction without a difference? It’s not just that blacks happen to occupy the lower ranks of America’s wealth tables. It’s that the economy and our political system, even as they promise equality, are stacked against us: From America’s beginning, slave labor funded the affluence of those who counted as citizens. Political reform has not yet brought economic parity. The median white household is worth around $141,000 today, but a typical black household’s wealth is only $11,000.

Interestingly, not all gentrifiers are comfortable with the change they’re bringing. “I couldn’t afford it, and I’m relieved,” Rene Gatling, who moved to Harlem in 2009 but left in 2014 for Connecticut, told me. But it wasn’t just price that persuaded her to leave. “Suddenly I thought, Why is there no anger, no push back? Our being here is pushing people out.”

Blacks who relocated here when Harlem was still affordable have been disillusioned, too. When I told Sharifa Rhodes-Pitts, who wrote the elegiac book “Harlem Is Nowhere,” about the group Save Harlem Now! just the name made her respond, “It’s too late.” She said that she and her young son were moving out. “It costs too much.”

Still Harlem endures as a community with high hopes, and in 2013, we felt sure we had found a champion. Bill de Blasio ran as the mayor for everyone, which we figured had to include Harlem. Black voters were crucial to his victory, and we thought we were covered and cared for. He even has a likable son, as liable to get stopped by the police as ours might.