Quantum computers are among some of the most complex pieces of engineering. They generally require a relatively sophisticated understanding of mathematics and physics, much of which is very non-intuitive (e.g., high-dimensional Lie groups, random probability distributions of probability distributions, low-temperature thermodynamics, ...). Piecing it all together requires careful threading. I think Gil’s notes don’t represent the pinnacle of rigorous care, but it is a useful “punch list” of broad considerations worth talking about.
I am not questioning your or anybody’s intuition directly or personally, but it’s easy—especially for the tech-savvy world of software engineers that frequent HN—to jump to conclusions based off of our intuitions about the mechanics and failure of (classical) systems and make (baseless) conclusions about contemporary quantum ones.