I am a PhD in literature—medieval literature to be precise. Yes, much of what is considered canonical in literature is boring, but the complexity that is lost on so many is what makes literature what it is. Clancy is topical, and a requirement of “true” literature is that it must be universal. Is Clear and Present Danger going to be something everyone can relate to? I think not.
And just to rip off from Samuel Johnson, a work needs to have at least survived for 100 years before it can be considered truly canonical. I’m not saying that I agree, so make of that what you will.
I don’t see the universality of a lot of “literature.” I’m not likely to pick up Dickens or Melville if there is a Clancy to read... even if I’ve read it before.
On the other hand, Sherlock Holmes is great stuff. Is that considered literature?
That's not to say that all ‘great’ literature is bad, obviously it is not. But so much of it motivated by Marxism, Freud, and such is garbage, whose pages aren't fit to use as toilet paper. I don't have a PhD in lit, although I do have a PhD, and I've read enough of the stuff to know.
I am now too old to read what I do not like, and so I don't.