When you have Harry Potter mentioned in your own question, I think you already know the answer =). Yes, if this is the general idea on what a character-study narrative is, then of course it can be found enjoyable by the mass audience both for the plot and the development of the said character. Come on, HP books are huge.
But what the literati mean by the character-driven books is not, I think, what they see when they look at HP. HP is a mystery book disguised as a magic book. Every book of the series has a very strict detective plot underneath it. No, it is usually not considered character-driven in the artsy-fancy circles. ASoIaF is not character-driven as well, (at least not in my opinion) because it is a tragedy that relies heavily on chance and, again, plotting. Haven't you heard how everyone started insulting the Tv show after they ventured into the solitary sailing, without Martin's plot structures to support it? Arguably, it became more character-driven, if it ever was so to begin with. But... no, it isn't better because of that. The plot of the first three books is what holds ASoIaF together, and whatever people are saying about TV show writers' inability to follow those up with the latter seasons... isn't Martin also not quite well-received after the third book? The fourth and the fifth books he wrote are entirely character-driven. Do people like them as the previous ones? No, not nearly as much. They are inherently plot-driven, and without it they lose something.
Night Circus is romantic (as in Romanticism ideals and all that), and romantic lit was never character-driven, take Moby Dick, for example. So is Frankenstein. Detectives and adventure books are not character-driven books, let alone the fact that they are serials and are not meant to be read as a "one installment". Yes, even the Simpsons make Homer fleshed out throughout their many seasons. Does that make watching a single episode of Simpsons character-study? I think... not, but maybe that depends =). Romance novels might be more... character-driven, I believe, but that is because the genre stems directly from the literary, by which, I presume, most literati understand the classic --> realist --> modern lit. After all, Pride and Prejudice verges on being a Romance novel, no?
Not to argue with you, OP, but having characters inside a book does not make it a character-driven book. Character-driven is Anna Karenina or Brothers Karamazov, or Disgrace, or Beloved, or even Forsyte Saga... It doesn't have to be extremely good or even enjoyable, it merely has to be all about the characters, nothing else. Can you describe the plot of any of these books? The premise is not exactly a plot. Yes, Anna cheats on her husband. (So does Bovary, so does Effi Briest. You can still see the baseline differences between the books even though their premise is the same). Is that the plot? No. The plot is... essentially nonexistent, and that kinda makes it entirely character-driven.
Yes, good books try to have both the character development inside them and the plot to entice the reader, but rarely books outside of literary focus on characters at the expense of everything else. But that is probably not what the aforementioned literati mean when they say that genre cannot be character-driven. They basically say that without plot or other necessary gimmicks, genre stories sort of collapse.
Now, when I see a book on the shelves that is both fantasy and has no plot inside it to even cheatingly describe it so that I can understand, then we will be talking.