Southwestern Florida needs some sort of commuter rail desperately down there. However, Southwestern Florida is far more retiree-centric than any other part of Florida, so I can't imagine there are many people who commute to city centers, like seen in South(eastern) Florida. The sprawl in Southwestern Florida might also make getting a commuter line going more difficult, as you'd have a ton of parties/communities lobbying to be served (or avoided) by the train.
The furth south on the western end of the Florida peninsula you go, the more it looks like CSX has been jumping ship on their routes down there. Which could be beneficial, since that means no more freight traffic to compete with, but the Legacy Trail (and other trail interests) have been pretty aggressive and quick in swallowing any RoW that gets abandoned.
IMO the Tampa Bay and surrounding communities, would be better served by multiple light rail lines along their sprawling hub-and-spoke rails, than traditional heavy commuter rail. I'd also imagine light rail would be more digestible for the NIMBYs there.
Speaking of NIMBYs, I do not know what the political situation in Southwestern Florida is like, but on the Eastern part of the Florida Peninsula, we all know about the NIMBYs, who had a fair amount of financial and political connections, fought tooth and nail to fight Brightline there - and they failed, miserably. They didn't even delay Brightline's construction, at all, if I recall correctly. Now, if that scenario were to happen in the Northeast, it's likely the NIMBYs would've stopped Brightline in its tracks.