I don't care about author intentions as much as I care about what author's actually achieve. Various creators of
Star Trek may or may not have intended for
Star Trek to happen in our universe. But overall they did no achieve putting
Star Trek in our universe, therefore it can not be in our universe.
Furthermore, I have to doubt whether many authors would choose to say that their stories happen in our universe once the concept of alternate universes was explained to them. There are a lot of stories which don't give enough information about the persons, places, events, etc. in them for their existence to be proved or disproved. But many or most stories set int he past or the present do give enough information for the existence of most of the persons, places, events, etc. in them to be disproved.
For example, in "Spectre of the Gun" several people in Tombstone, Arizona in 1881 are seen. Some, like the Earps and the Clantons and JOhnny Behan, are historical. Several seem to have been created for the story, like "Sylvia","Ed", and "Barber". And I think that the creators of the show didn't expect that Tombstone city directories or the 1880 census would show that they existed in Tombstone in 1881, and if pressed would admit that would put "Spectre of the Gun" in an alternate universe if it wasn't based on Kirk's ideas about the old west.
Another unnamed citizen of Tombstone is thrown out of a saloon and shot by what later turns out to be Morgan Earp on October 26, 881,the same day as the gunfight at the OK Corral. Morgan Earp is later called:
And I have to wonder whether Morgan Earp ever shot anyone, or ever was involved in violence, except at the gunfight at the OK Corral or had such a reputation as a deadly killer. I expect that I would have read about it in acounts of the gunfight if Morgan had shot someone earlier that day.
So I expect that if they were pressed the creaters of "Spectre of the Gun" would have said either "Yes, the episode and
Star Trek happen in an alternate universe" or "The events in the episode are non historical because the Melkotians based them on Kirk's ideas about the Wild West".
And considering how much more sinister the Earps appear in "Spectre of the Gun" than in real history, let alone in the more flattering popular accounts in the 1960s, I have to wonder whether Kirk's ideas about the Gunfight at the OK Corral are based on family stories handed down over centuries from pioneer ancestors with the surname of Clanton or McLowery!
So what about episodes set in much more recent eras like "The City on the Edge of Forever" or "Tomorrow is Yesterday"?
If there actually was a 30th Street Mission run by a sister Edith Keeler in 1930 New York City they would probably be listed in old fashioned city directories or newer phone books. There was also a Floyd's Barber Shop in the NYC set, and Mr. Floyd also would have in the directories if he existed. And is there evidence that any of the boxers mentioned in the poster existed in 1930:
https://www.therpf.com/forums/threa...ng-poster-city-on-the-edge-of-forever.344880/
Since there was some uncertainty about the age of Billy Clanton at the gunfight at the OK Corral I once looked him up in the 1880 census which said he was 18, thus mking him 19 or 20 during the gunfight. I also once looked up the Apache leader Geronimo in the 1900 census.
So it should be possible to prove which of the characters in "City on the Edge of Forever" were alive in 1930.
There is a lot of information about USAF Captain John Christopher in "Tomorrow is Yesterday". Serial number 4857932. Married with 2 daughters in the late 1960s and a son Shaun Geoffrey Christopher born later. Serving in the 498th Airbase Group in the late 1960s. Lt. Colonel Fellini served in at the Omaha installation (which would be Offutt Air Force base).
So it would be easy to find evidence that they lived, if
Star Trek is in our universe.
And as it happens, the first man Moon landing, Apollo 11, did launch on a Wednesday. However, it din't launch at 6 AM EST. So unless someone can find evidence that Apollo 11 was originally scheduled to take off at 6 AM EST but the launch was set back a few hours, "Tomorrow is Yesterday" must happen in an alternate universe.
And If the creators of those episodes asked me if I wanted them to only look up and usereal persons in stories set in the present or the past, and thus risk being sued by those real persons, I would have said "no, I only want you to acknowledge that
Star Trek cannot possibly happen in our universe and must be in an alternate universe."
Using person, places, things, or events in a work of fiction which can be proved to be unreal automatically puts that work of fiction in an alternate universe.