It's important to define what each person means by "creative control."
Generally, when I see that used, it seems to encompass EVERYTHING. The author wants to design the cover (or choose exactly what goes on it), do the formatting (or choose the various options for typeface, etc.), write the cover copy or marketing description, choose the SEO terms, plan the marketing (or lack thereof), execute the marketing, and whatever else you can think of. The impression that's given is that to give up total and absolute say over ANY of these elements is going to violate the author's integrity.
In that case, I think it's just a silly reason for wanting to self-publish, since it's very unlikely that the author has a clue what a good cover, formatting, marketing, etc. is. Or at least unlikely that the author has a clue (and skill) in ALL of those categories, and they seem worried that giving up even one, where they're admittedly either clueless or incompetent, is unacceptable.
There's a middle ground, of course, where an author has control over sub-contractors. The author hires a cover artist and editor and formatter and marketer and business planner, etc. Yes, the author has "control" over the outcome, making the final decision. But even then, it's not as clear-cut as it might seem at first. For one thing, if the author doesn't actually know what an effective cover is, having control over that decision is just as likely to hurt the author's career as help it. (Sure, the author then can take full responsibility for the failure, without sharing it, but that's sort of cutting off the book's nose to spit its face, since, if the author ceded some control to someone with actual expertise, the book might have succeeded.) And why pay big bucks (or even not-so-big bucks) for an expert and then completely reject the expertise? Plus, I'm not sure how that scenario is terribly different from trade publishing, where the author generally has input into the cover, editing, back-cover copy, marketing, etc., just not the FINAL say, which is ceded to someone who's got actual expertise in the field. Sure, it depends where an author is in the ranks of other authors (bestselling, midlist or debut), how much of a say they'll have in the various elements, but it's wrong to suggest that it's all or nothing, or that "control" is necessarily a good thing, when the matter is something the controller knows nothing about.
Finally, I think the decision to not submit to a publisher that doesn't publish the author's stories is just not part of the "control" discussion, and it muddies the water. In that situation, the choice between trade and self is no different from the choice between submitting to trade publisher A or trade publisher B, based on their market. EVERY author has that control. If I'm writing cozy mysteries, I control the choice of where to submit. My stories aren't going to fit any of Harlequin's lines (I don't think they do cozy mysteries), for obvious reasons, just as they aren't going to fit any of a sf/f publisher's lines. That type of control is different from deciding, "Publisher A does a heck of a great job with cozy mysteries, but I'm afraid I won't have exactly the cover I envisioned on my book, so I'm going to self-publish instead." Or "Publisher B does a heck of a great job with cozy mysteries, but they won't let me have final say on the cover copy [and/or other elements], so I'm going to self-publish instead."
I guess I just don't get the passion with which some authors cling to the idea of controlling things that they really don't have any expertise in. It's particularly confounding when the person is someone brand new to the industry, who doesn't have ANY information about the process at all, and yet is determined to do what takes a dozen or more people to carry off in a trade setting.
Just as an example, we see lots of query letters in QLH, many of which are actually more like cover copy, and authors CONSTANTLY say that it was far easier to write the 400-page manuscript than to write the one-page query or cover copy. It's definitely not easy to write cover copy, and it's a specialized art, I think. I know I'm abysmal at it, and would be THRILLED to hand over the responsibility to someone else! I just don't get why the chance to do something I suck at is somehow a bonus.
Ultimately, I think it may come down to a personality thing. Some people have more control issues than others. I do like to control things, but I'm comfortable letting go of the stuff that I'm miserable doing or that I suck at. I'm guessing that the flip side of that personality is someone who likes control AND enjoys the challenge of learning to do the things they suck at.
And now I'm rambling.
TL;DR: whenever anyone says "I want control, therefore I self-publish," I really wish they'd say WHAT, exactly, they're planning to control, and what their bona fides are for being able to control it.