Terrible investment. The team makes very little income no one goes to those games
The price is extremely high for a bad product
Keep in mind they are also inheriting a shiny new taxpayer-funded stadium.
Regarding their fans, it doesn't help that the Marlins ownership the last decade or so has had little interest in winning. And even when they won a couple titles 15-20 years ago they didn't reinvest to sustain a winning culture. That was a mistake for an expansion team, though at least there was some effort back then. Recently under Loria they've become a glorified farm system for bigger-market clubs.
Whatever fans they have are probably pretty jaded.
Jeter doesn't strike me as someone who will be content to lose games; and the desire to win is contagious and should run throughout the organization. IMO fans can detect when they have motivated people in charge - the attitude in Boston changed almost overnight when John Henry took over the Sox. Same with Robert Kraft and Wyc Grousbeck.