It was clear to me...and Prime Spock's behavior is further evidence of the Prime Universe's continual existence. So, I don't need another story to clarify what I feel is clear enough and the rest is semantics. But, I can see the confusion-I just don't agree with it, nor do I think that Trek rules are so hard and fast as to be inflexible.
Prime Spock's behavior was out of character. It showed bad writing, not a statement one way or the other.
But how is it clear? We don't get any evidence that there was anything special or different by this method of time travel. Look, I'm all for the prime universe still existing--but the writers didn't make that happen. Certain rules, once made, must be hard and fast. You can't establish that if you travel in time, history can be changed, and later say it can't. The two views are polar opposites.
They've never actually established solid rules for time travel, yes most of the time travel stories have involved resetting the timeline, but we've never gotten any indication that that is the
only way time travel works. All the first Kelvin Universe movie did was introduce a new way for it to work.
Kirk Prime, I highly recommend you read
DTI: Watching the Clock, it establishes a specific time travel system that does manages to include both time travel systems in a way that makes sense.
I will try to remember to check this book out, but I find that often, book writers are simply better than TV and movie writers in Star Trek. That's why I was such a big advocate for Star Trek to hire Judith and Gar Reeves Stevens. I was rewarded with a clear improvement when they actually did. Granted, they were sprinkling sugar on a turd at that point, but there was a definite upgrade and a frustration as to what could have been had they been there at the start.
Regarding a means of time travel where you go to another universe--again, I am not saying that it can't happen. It would be something like what happened to the Tholian Web Defiant. That ship went back in time 100 years AND moved to another universe. However, they made that very clear in the show. They did NOT do that in ST09. Books are not canon, much as I wish some of them were. I would LOVE a story that proves me wrong.
It CAN be done. It just has not been done. I actually think it would make a great story too.
Perhaps, unless a specific phenomena is protecting them (e.g. the Borg Sphere's temporal wake in First Contact), the time traveler is protected up until the point where either (1) their existence is completely precluded by events in the new timeline or (2) they catch up to the point from which they left. So, perhaps the alternate Tasha Yar from "Yesterday's Enterprise," had she not been executed by the Romulans, would have spontaneously disappeared either once the original Tasha Yar died in "Skin of Evil" or once the date of the original events of "Yesterday's Enterprise" had passed. Similarly, perhaps Spock Prime, had he not died of old age, would have survived until either young Spock died or until the new timeline caught up with the moment when he & Nero left the old one.
To throw another Star Trek example out there to complicate things more-- "Time Squared." IIRC, the future versions of Captain Picard & the shuttle suddenly disappeared once the present version of Captain Picard took decisive action that precluded that other past from ever happening.
This is a harder one. But we do have examples of the time traveler being protected in a variety of ways. Time Squared was a specific phenomenon that seemed to be different than other examples. For example, why couldn't that version of Picard just have a conversation? It made no sense. Sometimes they carve out different things. But when they do, they are fairly clear.
The prime universe could still exist post-Kelvin. We just haven't had any concrete proof.
There's a lot of unanswered questions there. I mean, Doc and Clara are still in the past and it must have taken Doc a significant amount of time (sorry) to build the TimeTrain, so did they return to Hill Valley or start lives elsewhere to avoid anyone connecting them with Eastwood's death? How did Doc avoid contaminating the timeline (not that he seemed to have been worried about it previously)? Was Doc being in the past a predestination paradox? Was there a timeline before Doc was stuck in the past, and if so, how did it differ?
Oh, and what happened to the Hoverboard?
There are some amazing fan fics out there by an author named Mary Jean Holmes. Novel length and level. Continues the stories. If you can find them, they are worth the read.
I assume he adapted the Hoverboard tech to make the train capable of flight, but in terms of time travel, I would think they'd be entirely different fields.
Doc would have had to somehow use his knowledge of the future to make money. As much as he would hate the idea, he could justify it by saying it was to bring his family to the future, not for actual personal gain, and he would spend every penny he made to fund the train, which would not leave an estate behind.
No, I'm presenting my theories as opinions. I'm not claiming that Trek ever established rules, because I don't believe it ever did. Even if TOS had established rules, it was a show created in the '60s and reflects an understanding of science from that time period.
In any case, I don't see any reason to believe that "alternate timeline" and "alternate universe" couldn't have been being used interchangeably. I'm willing to bet plenty of posters to this forum have used the terms interchangeably, so why not Our Heroes?
Hell, there's plenty of people in this forum who use the term "cannon" interchangeably with "personal continuity", for multiple reasons.
Universe and timeline are completely different terms. They aren't interchangeable. Neither are personal continuity and canon.
There is nothing in 2020 that has changed since 1966 that would show anything about time travel is wrong. No one has gone to the past that we know of.
With that in mind, nothing can be right or wrong in the real world.
I'll accept that, but even going back and looking at the posts your tone is pretty similar to KP's. For what it is worth, I am on Kirk Prime's in this regard--canon is what is seen onscreen until demonstrated otherwise. It is fun to surmise and connect dots, and overthink things more than writers ever did, but until stated onscreen it is conjecture.
Doing that is a weakness of the writing, but a strength of the fans. Sometimes you have no choice, like when there is a blatant contradiction. Valtane is one such contradiction which invalidates the episode Flashback. But something like this? We have to go with what we saw, and wait until they fix. Fortunately, fixing this is doable and a strong story can come from it.