It's pretty much impossible to destroy the value of a franchise. The A's were purchased in 2005 for $180 million, and are worth around $1.2 Billion despite the fact that they have done everything possible to drive away fans as they relocate. that value will skyrocket once they are in their shiny new ballpark, something that will never happen here but could easily happen in Nashville.
Explain why the Sox do nothing from a marketing standpoint, continuously drive away season ticket holders by ignoring them and jacking up prices, hire the least competent people for key positions, and don't bother hiring even the minimal number of staff to work the ballpark. Nobody is this incompetent, and you can argue with JR's decisions over the years, but there was never a point in his ownership before the last couple of years where everything went to s%*# at the same time as has happened.