Offense may sell patrons and network eyeballs, but I believe the Cowboys are past that. They get games nationally televised and full stadiums because they are the Cowboys. Offense doesnt win you the ultimate prize, defense does. If the Jones's want to make money there is no other prize then the Super Bowl that will make them a boatload of it.
If trading back allows you to solidify the defense they should be all over it considering their offense is already a top 3 in the NFL anyways. Imagine if the Cowboys had a top 3 offense and top 15 defense? Where would that put this team?