They are tearing down the team and unloading big contracts in exchange for prospects and draft picks. Most notably, they traded Giancarlo Stanton to the Yankees.
Personally, I think the strategy is correct. As constituted, the Marlins were missing too many pieces to become a consistent playoff contender and were carrying too much payroll to do anything about it. Stanton's contract, despite his talent, is ridiculous, something only the Yankees and maybe the Dodgers could afford. If he pulls off an Astros style rebuild, the fans will come back.
The problem is that Miami has done this teardown thing several times, especially after winning a World Series.
Fans are just tired of it.
I have a cousin down there, usually drive down to catch a Reds game with him. Just this last weekend, looked up tickets for the day we both have open...
https://www.mlb.com/marlins/tickets/specials/mexican-heritage-celebration
Maybe next year.