If the argument is that there is only room for one MLB team in Chicago, while there is a market for a MLB team in the suburbs, the SOX are the logical team to move when the time comes. As mentioned, the core SOX fanbase is no longer on the south side of Chicago.
Rickett's should throw everything he can into rebuilding Wrigely in it's current footprint/location, even if that means shutting the ballpark down for 1-2 seasons as he rebuilds the grandstands, concourses and upper deck from the ground up. If he does, he will pretty much be guaranteed 3 million fans each season wanting to visit historic Wrigley Field and perhaps actually see a Cubs game while they are there.
I've enjoyed going to SOX/Cubs game at Wrigely due to the party atmosphere. I wish the SOX had a similar atmosphere outside their ballpark but no matter how much they try, they still only have the nicest house in a bad neighborhood.