“The Final Countdown scenario involved a type of wormhole or a gate that allowed a ship to go back in time in an unexpected unplanned event. Rather a unique approach in time travel.”
Yes, I know that in The Final Countdown scenario it didn’t involve a man-made/created portal, as on the Philadelphia Experiment.
The theories out there is that both, man-made/created, or natural portals (or wormwholes) do exist.
A lot of evidence seems to corroborate both actually do exist.
As for the possibilities of changing the past in order to change the future, I’m convinced there is some universal law that forbids that to happen.
Or if possible, then different timelines for the future will be created and both co-exist in the future. Meaning that those in a timeline will never know about those potential changes in the past, as both will follow different paths…
I like some of Stephen King’s books (in films, as I’ve never read one of his books), but IMHO that theory is wrong. As I say above, by changing the past, nothing would change in that particular timeline, a new one would be created instead.