I can't pretend to be a city growth expert. But I think some blame is on the University of Louisville.
Nashville has added the Predators of the NHL and Titans. They also started hosting SEC tournament and NCAA tournament and a dozen big concerts per year. Also, you have Vanderbilt attracting high achieving kids from a wide area.
Yum center opens and UL blocks nba expansion. Maybe have two concerts a year. And now no one goes to their basketball games. And while a Louisville degree is no less legitimate, it's not necessarily attracting young people in to the city.
I mean really at the end of the day it comes down to jobs. Whoever has the most companies and industries attracts the most people for work. Columbus for example has a very diverse market with banking, insurance, healthcare, retail, restaurant etc headquarters. Just like Austin, Charlotte, Nashville etc. Some were reliant on one industry and weren’t diversified so they got hurt (Cleveland, Detroit, Pittsburgh). But some cities like Pittsburgh that were heavily reliant on one industry (steel) have made a comeback by attracting different diverse corporations. Attracting the different corporations is the hard part imo. Favorable taxes, a diverse employee pool to choose from, universities close by to recruit from, etc. there’s all sorts of ways to attract corporations but I think that’s the tough part and requires really organized and smart leadership.