The Miami Marlins new ownership knew what they were getting in to when they bought the team. They were aware of the debt they’d be inheriting, and had a plan to get out from under it. At no point did that plan included keeping the team together.
The wanted to build organization depth. The best players in their system were already at the Major League level, and were only winning 77-games a year. With a weak starting pitching rotation, they were going to have to spend big in free agency to compete.
New ownership didn’t want to do that.