But TOS *was* made in the 1960's, and set and ship design can be changed as easily as an actor is recast.
Right. The TOS ship didn't look the way it did because it was exactly what the creators wanted, but because it was the best approximation of future technology that they could manage with the limited time, budget, and resources at their disposal. That's why they changed the look so radically for
Phase II/TMP -- because by then they had the budget and tech to make it more sophisticated. Same with the makeup. When TMP came out and showed us ridged Klingons, Roddenberry explicitly told fans to accept that Klingons had always looked like that, but TOS simply hadn't been able to show it. His own view was that what we saw was just a modern attempt to approximate a conjectural future, and that fans shouldn't take its every detail literally.
Unrecorded (for whatever vague reason) first contacts have happened in Trek before - Robert April and George Kirk learned the Romulans' secret in Diane Carey's Final Frontier, the Borg's initial encounter was rewritten in Voyager and Enterprise (and at least one TOS comic)
Not to mention in real life. Europeans first settled North America in 1000 CE, the Norse colony of Vinland. The Vinlanders and indigenous peoples interacted, traded, and fought for years before the colony was abandoned. And then it was completely forgotten about, so that when Columbus stumbled upon North America nearly 500 years later, it was believed for centuries to be the "first contact" between Europe and the Americas.
I do wonder what the TOS Enterprise would have looked like had it been the ship destroyed in the opening scene of ST XI (as was the plan, before Abrams was told that it was strictly forbidden to destroy an Enterprise) instead of the Kelvin.
Probably much like the
Kelvin did, interior-wise -- suggestive of the overall look and flavor of TOS design, but considerably more modern and detailed. After all, the film was targeted mainly at creating a new audience for
Star Trek, bringing in moviegoers who weren't already devoted fans. And winning over modern moviegoers would require giving the film a modern look. Not to mention that the feature film screen, just by virtue of its size and resolution, demands more detailed set design than the small, mediocre-definition TV screens that TOS was made for. Basically, TV design back then was more impressionistic, more about the broad strokes than the details. So a more detailed, technically advanced design that captures the same overall aesthetic is a valid way to recreate it.