This was a human interest piece; IMO it was less about the factual impacts of gentrification and more about the emotional baggage that white people feel about it. This was the author's way of coping with the destruction of the history in that area: to record it so that it may be remembered.

And IMO the feelings of guilt are the stereotypical "white guilt". Progressive white people feel guilty about the situation that black people are in because we benefit from the institutionalized racism that they suffer from. But we can't really do anything because we don't understand what being a black person in America means.

That means many of us end up confused and feeling guilty because as progressive white people, we want to help. But we can't, so we end up writing about the history that we're destroying as a means of making it ok to ourselves. But ultimately, this is the kind of "local history" that is often lost between generations regardless. It's likely nobody remembers who the neighborhood patriarch was in their neighborhood 100 years ago, so this isn't a phenomenon restricted to gentrified areas. It's just that gentrified areas are filled with guilty white people (who are far more likely to write a tome and post it on Medium than someone poorer and less educated).