It's hard to make the case that Hackensack is "gentrified", since the value of a house in Hackensack is so much lower than the identical house in Fair Lawn, Paramus, Oradell, or Westwood. Even Maywood. It used to be that a single family house in Hackensack was about 80% of the price of the same house in northern Bergen County, and now it is less than half. And so much more really upscale housing has been built in the northern towns that Summit Ave is no longer one of the best streets in the entire County. I remember when Summit Ave was better than ANY street in all of Paramus.
Also, nobody can realistically complain about gentrification in Hackensack because the school system went from integrated to almost entirely minority. Granted, most of that happened 1985 - 1995, but it still happened. The income level of students' families has also gone down, as have the performance on standardized test scores.
The battle is not gentrification versus affordable housing, the battle is to keep or make neighborhoods and the downtown attractive to the mainstream population, meaning everyone of all backgrounds. Otherwise, we slip back and become another Paterson.
If people want to complain about gentrification, those complaints may have some validity in Edgewater, Hoboken, West New York, downtown Jersey City, South Orange, and Maplewood. But not in Hackensack.