OP's got a point, namely that it was William Shatner who said the monologue, so it had to be tailored to... his 'unique' way of pronouncing words. This is the same guy who can't even say the word 'sabotage' properly, after all.
^Huh? What's pronunciation got to do with word order? And how is Shatner's pronunciation of "to boldly go" in any way unusual?
When I was a youthful man, I bore bruised knuckles for my grammatical mistakes. Back in the days when teachers thought that any straying outside the lines meant a life that would generate chaos in society, rather than order, so they fought hard for students to abide by their lofty albeit misguided principles. They can't do this any longer. The power of the teacher has been plundered, all in the name of freedom. Today, stalwart languages around the world are being frayed at the edges by the burgeoning youth, a group with a buying power that the consumerism machine beckons. Thus, the grammatical mutations made are tolerated and embraced for the profit making hidden agenda. Therefore... the rules really don't matter any longer. If you bastardize the grammar, you can call it "artistic license" and boldly walk away with indignant pride.
... to boldly walk where indignant pride has gone before. 2. Shatner and his vocal talent could have well pronounced any sensical permutation of the intro.
It's not. But lines can be tailored to suit the actors who are saying them. Kirk's preamble was by various accounts one of the last things settled on by the production team in TOS, and a few versions were tested. Shatner is the king of speaking iambic pentameter, and that particular arrangement of the phrase suits both him and his character, Captain James Tiberius Kirk. There's no shame in that whatsoever.
While the pseudo rule about not splitting infinitives was indeed made up by guys who believed Latin was, somehow, the perfect language, it's been propagated by certain English teachers (and yes, I am thinking of you, Mrs. W) who just adore nice, firm, unequivocal rules. And the same people invariably say you shouldn't end sentences with prepositions - and there's no rule against that either. As an editor who has to read a lot of ill-written dreck, I wish they'd concentrate on teaching kids how to write ordinary prose and leave unnecessary complications alone.
As a writer of fiction, I'm often frustrated by copyeditors who place strict adherence to arbitrary and often artificial grammatical rules over good writing -- for instance, replacing a perfectly smooth and euphonious construction with a painfully awkward one just to keep a sentence from ending in a preposition, or harping on a totally imaginary rule (actually just a suggestion some grammarian made that later style guides somehow chose to interpret as an absolute doctrine) about when to use "which" and when to use "that." What particularly bewilders me is when they do it in dialogue passages, as if it were reasonable to expect people to use perfect, formal speech all the time. Sometimes they harp so much on grammatical and structural precision in dialogue that they bulldoze over intentional choices I made to convey character and emotion. It takes a lot of work to fix such "corrections."
That reminds me of words probably incorrectly attributed to Winston Churchill, noted in the Wikipedia article on hypercorrection: "This is the kind of tedious nonsense up with which I will not put!" --- On the question of how the Star Trek prologue was written, there's a Wikipedia article at http://en.wikipedia.org/wiki/Where_no_man_has_gone_before. I'm not satisfied with the citations in it, though, one of which is a secondary source at http://www.cbc.ca/news/indepth/words/infinitives.html. That CBC article, which itself discusses the split infinitive issue, is a good read, but it's not written in a way that makes it unambiguously clear what it's getting from Inside Star Trek. Perhaps someone can confirm that the whole narrative of the evolution of the prologue in the CBC article [beyond just the first draft] comes from Inside Star Trek? Anyway, if the narrative is accurate, then Shatner's diction had nothing to do with the wording. Roddenberry finalized the wording without Shatner's involvement to beat the deadline to get the opening credits in the can, then dragged Shatner in for the recording at the last minute. Thinking back, though, I'm not 100% sure that every TOS episode aired besides Where No Man Has Gone Before had the prologue, at least in all their forms. I seem to recall that one or two more of the early episodes aired during syndication didn't have the prologue either. Can anyone help me settle that?
Everything in it comes from Inside Star Trek except for the bit about the Justman memo proposing that "United Space Ship" be shortened to "USS" in the narration. Yes, it doesn't seem remotely likely that something like that would be tailored to the actor's delivery. An actor would be expected to be capable of delivering any line as written; that's one of the basic parts of an actor's job, after all. The actor might have trouble with some phrasing or other on the stage or in the studio and suggest a variant that flows better, but that doesn't seem to be the case here. It's worth noting that "to boldly go" doesn't appear until the final draft, which seems to have been put together a bit hastily to meet a deadline. They wouldn't have had time to polish it to fit Shatner's delivery. The split infinitive may have happened because of the rush to get it done, for all we know. I don't remember any episode other than the second pilot lacking the narration. But the second pilot was often aired as part of the syndication package, and if you saw it multiple times over the years, that could create the impression that more than one early episode lacked the narration.
This is surprising, especially in mass market fiction as opposed to, say, nonfiction at a university press. Everywhere I look I see the old, picky rules violated; I thought no one cared.
^Well, it's copyeditors' job to catch and fix mistakes. Some just get a bit too mechanical or overzealous about it, or don't see the creative factors that override the letter of the style guide. Which is why copyedits are sent back to the writer for approval and revision.