Exactly, gentrification wouldn't be going on if economic revitalization wasn't needed. I'ma quote Gil Scott Heron "Since change is inevitable we should direct the change rather than simply go through the change."
I think it still would be going on whether urban areas needed urban renewals or not. I say this because places like NYC, Detroit, Charlotte, Louisiana, etc are great places to own successful commercial industries like shipping ports, manufacturing hubs, fishing, and entertainment outlets because of their locations and the profit potential. This is what many groups see blacks wasting in the inner cities. This is why Detroit is currently being bought up by China and NYC slowly becoming white again. People are saying to themselves, "Look at the blacks waste all of that opportunity in the inner city. Let me slide in and buy it from them and show them what they could have had when I make a killing for me and my people".