You will need a major change in politics in TLH. If they killed Sun Rail and loose access to federal dollars that some other state will likely get, I don't see them backing state subsidized Amtrak service. Florida is certainly ripe for expanded passenger train services as well as commuter rail in the major areas to be similar to Tri Rail. If the pols don't get their act together, it will be tough to do anything.
One huge problem in Florida is that you have a large number of retirees from the high-tax states in the northeast that came to low-tax Florida and want to keep it that way, and these people get out and vote at a very high percentage so they have clout out of proportion to their number. The problem is that they want the services that can only come with a high-tax regime. The second problem with these people is they would like to keep the state as third-world as possible otherwise. Therefore, there are major funding problems with such things as the education system as that is in most states a fairly high percentage of the cost of a state government.
Besides, why do they care about the local yokels getting a good education or anything else that would work against having a good proportion of low skilled low wage people to do thier work, except of course in things medical. So, why would these people care about education in Florida? Their kids are grown and their grandkids are in other states, and gofers, gardeners and caretakers do not need lots of education. Transportation is somewhere in between. It would be nice if more were spent on transportation facilities, but when it relates to their day to day situation that does not mean a lot to these people.
Thanks to the terrain, Florida would be an easy state in which to set up reasonable speed passenger services between major in-state points. At the least, start with about 3 to 4 a day between Tampa / St. Pete and Miami, Tampa / St. Pete and Orlando on to Jacksonville, and build up from there.