Started out with average zooms, then collected primes, then found that I missed too much opportunities by always having the wrong prime mounted. Finally settled on 24-70 II as the main lens.
But even when I am using the zoom lens, I will now consciously choose a focal length that I intend to use and shoot away. So now using 24-70 II my photos come back with EXIF showing 24, 35, 50, 70 but not much in between. To me it is a bag of primes on it's own.
Prime lens are very good at training your sense of perspective and low light stuff. But once you go over it, you will appreciate what a good zoom can offer.
Every single word you wrote I agree with completely 100%, it's like I wrote it myself.
I have two primes currently, but they are WAY different than a "normal" fast prime in the 24-70 range, so they have a few tricks the zoom doesn't have, but shooting the 24-70 makes no difference where I used to shoot my primes.
But since I change my mind every so often, the 35 L II is THE lens I want. I miss the old one