Good theory, but IMO NashVegas is growing & booming with people who are going to maintain their Fandom of wherever they came from & will not adopt Vandy. People from East Tenn or Kentucky or Georgia or Alabama are not gonna say "welp i live here, time to dump the school me & my family have always cheered for!".Nashville and surrounding region are booming in population and industry as well as becoming a big destination town for travel. Having that market is going to start paying off for the SEC.
All those people are going to look for a team to support, all those businesses are going to look for advertising/sponsorship opportunities.
Vandy is the sleeping giant. They have the alum wealth, they have the SEC brand/money, they have the city, they have entertainment industry/pop culture, big star power/brands right next door...
Ive spent time in growing southern cities, Charlotte, ATL, Orlando. The new people don't become fans of the local teams, they generally stay attached to the teams/schools where they came from. Does Georgia Tech have a great fanbase, hello!?!? And their teams have been a helluvalot more respectable on the field than Vandy. ATL remains a hodgepodge of fanbases, UGA, lots of Big 10 folks, other ACC schools. UCF has very very slowly built a little bit of a fanbase in Orlando.
would be a nice story if Vanderbilt became a winning football program with a full excited stadium of folks mostly wearing black & gold. I just don't see it happening soon.