Saying that, I did meet someone who awakened without a teacher. I suggested that he attend a couple of sitting groups that I used to go to. After the Dharma talk/discussion at each group, without having said a word, both teachers came up to him and basically said, how on earth did you do that?
That's an awesome story. I'm only scratching at the surface, and something tells me that it's going to take a lot longer than that, if ever, for me.
but then again, practicing for 5, 10, 20+ years and awakening is also not guaranteed.
For most of us, for sure. However, on the positive side, even many lifetimes of trying is but a mere tick on the clock of samsara. :)