Unfortunately Nashville International Airport doesn't have very many non-stop transatlantic flights so the geographic proximity savings is often eaten up by time spent connecting.
Property taxes are lower. TN has an average property tax rate of 0.9x%. Los Angeles County has an average property tax rate of 0.5x% (i.e., nearly half). Property taxes in LA are only higher on an absolute basis because the property subject to tax is worth more.
There is no richest town in America as a single individual moving anywhere could make it that overnight.
Also just prima facia there is no way belle mead is as rich as billionaires row Manhattan, Pacific Heights in SF or Bel Air in LA. Let alone the Hamptons/Jackson Hole zones.
By what metric is this city the richest?
Others that vary by person: political conservatism, smaller city, closer to everything besides the West Coast.