You are in effect making the argument that "tough learning" has no place in the curriculum. It's absolutely crucial that students are confronted with learning curves that are discontinuous compared to what they have previously faced. The other road leads to common denominator mediocrity. The real problem is that you cannot set an individual curve for students because of the need to teach them en masse.
The most significant experiences in my life have been about overcoming learning curves that seemed insurmountable. Two experiences stand out for me, one with mathematics, the other with literature. Even one experience like that can last you a lifetime. It can lead to a career and a lifelong passion.
My epiphany in mathematics came at age 16, the one in literature much later at age 22. The reason both came so relatively late was that my arrival was by circuitous paths of self-study. Unfortunately I never had a truly inspiring teacher.
I'll say a little (or a lot) about the epiphany I had with literature since you seem to have a particular problem with canonical literature. Until my teens, I read more than most kids but not very much and virtually nothing but pulp fantasy and science fiction. When I became interested in programming and later mathematics I read a lot of technical books in those areas. But anything vaguely literary with a challenge accompanied by no immediate reward was a complete turn-off.
Poetry in particular was incomprehensible to me. I could not understand any of the poetry we covered in school, and I could not understand how anyone could understand it, much less appreciate it. In short, my attitude was the same as yours: All these people who pretend to love it must be pretentious pricks all hoodwinked by the Emperor's New Clothes.
I eventually stopped reading almost any fantasy and science fiction and stuck to nonfiction, mostly technical material. But when I was age 22 I picked up a copy of Pullman's The Golden Compass and read it through in one sitting. I thought (and still think) it was the best work of fantasy I had read.
I looked the author up online and found that elements of the books had been inspired by Milton's Paradise Lost. I had heard of this work but never read it. I swifly found a free copy on Gutenberg and discovered to my dismay that it was a narrative poem. A fucking poem! But this writer guy says it's the best poem in the English language, so there must be something to it. I tried to read the first page but was defeated by Milton's tortuous syntax and mythological allusions again and again.
I gave up and told myself that poetry was simply not for me. But at least I had now convinced myself that this kind of old and difficult poetry was not an elaborate inside joke or some sort of hoax.
A few months later, after rereading The Golden Compass, I decided to give it another shot and this time ordered a handsome printed copy that incidentally came with an introduction and a chapter by chapter commentary by Pullman. This time I forced myself to read everything aloud and that was the trick that let me crack it.
Wow! Poetry should be read out loud!
For some stupid reason this had never really occurred to me. Soon I had gone through and understood the first several pages. Suddenly I could read and understand the poem with surprising ease. It was the most sudden zero-to-hero experience I'd had in my life. I was covered in goosebumps and tears were welling up in my eyes. I was forced to stand up and pace around the room for several minutes to calm myself down. Finally I sat down and spent several hours memorizing the first couple of thousand lines, despite my generally awful memory for such things. After that experience I found I could read through a book of the poem at the rate of one per night. Not all the allusions made perfect sense on a first pass, but now that I had learned to sound out the words the syntax was no longer an obstacle at all.
The poem possessed me so completely that I eventually memorized the first two books of the poem almost effortlessly, possessing the poem in turn. And when I say memorize I don't mean by rote but by the kind of compulsive rereading and rethinking that only passion can motivate.
Anyway, that was my epiphany. I decided to try Shakespeare next and bought a copy of Midsummer Night's Dream. That was a lot harder! The word to word, sentence to sentence writing of Shakespeare is so far beyond the likes of Marlowe, Milton or Melville in terms of subtlety and modulation. All of those guys are at their best when they write majestic rhetoric blasting on all cylinders. That's not to say they lack subtlety in other areas; both Milton and Melville are incredibly deep.
Anyway, I slogged my way through Midsummer Night's Dream. It was fun but it didn't deliver Milton's spine-tingling bombast in the same way. It was subtle the way the world is subtle. If you read it superficially you are likely to leave with little else but the plot and a general but vague sense of the characters. Shakespeare's plots are expendable and the strength of his characters are in their variety, distinction and depth, so this way of reading him does him poor justice.
I put aside Shakespeare for another year or so. My next attempt was with Hamlet and that was what cracked Shakespeare for me. It had all the gratifying high rhetoric I so loved about Milton but it also had complexity in subtlety and depth to last you an infinite number of rereadings. From there I eventually went on to read all of his works. Unlike Paradise Lost, several of them took me several rereadings to love. They rarely give away their secrets on the first stroll through.
Holy crap was that ever long. Anyway, I present this as antidote to your criticism. What this and a few similar experiences has taught me is to never assume that something is a worthless sham simply because you don't get it right away.