The Orlando area theme parks (or even local transportation) could solve the problem - if they chose to do so (or had the money) The bigger problem is at the other end.
I could take a train to Orlando - but I would have to drive 30 minutes north to do so, and leave my car. Then take 3 hrs by train. Then need transportation at the other end. Or I could get in my car, and drive south for 3 hrs and park at my resort.
And I live downtown! It would be even harder for someone who lives in the suburbs. Pretty much impossible without a private way to get to the train station.
Before the downtown terminal was closed back in the late 70s, I could have taken a cab or bus. Even earlier, I could have taken the streetcar.
There also has to be the will of the Florida taxpayer!
No, there has to be the will of the Florida Legislature. Do you not remember the Bullet Train? The Florida voters voted to make that train constitutional, granted is not the way to do it, but many times the only way for Florida citizens to get the Legislature to do anything. And what happened? A somewhat misleading campaign by Jeb Bush to repeal the amendment. Now look at I-4. Wouldn't it be nice to have that train? Federal government was giving money away to the states for things like high speed rail development (it was a return of OUR tax dollars). What did Scott do? Turn it down.
Obviously you live in Florida since it would take you 30 minutes to drive to the train depot. I also live in Florida. I would love to be able to drive my car the 15 minutes to the train depot (we have one, just not operating anymore), park it there and take the train to Orlando. I stay on property and take Disney transportation, so I don't need transportation once I get there. And I think Disney would provide something similar to the Magical Express from the Orlando train depot to your resort as is done now from MCO to the resort. Given how congested the 4 major roads in Florida have become - I-10, I-75, I-95 and the Turnpike - I would welcome high speed rail between Miami, Tampa, Orlando and Jacksonville. Just ask the members of the Florida Legislature about getting to my part of the state during session.
As I previously said, one of the plans for the Bullet Train from Tampa to Orlando - the busiest surface road in Florida - was to run along the I-4 corridor, some proposed in the median. I've ridden CalTrain up to San Jose, through a much denser population than Florida has. It can be done. Folks in Tallahassee just have to see the wisdom of doing so. And my experience with the Florida Legislature is that what they lack, wisdom and future thinking. And btw, it was Henry Flagler who is more responsible for the expansion to South Florida than A/C.