I agree with everything you said except the 2nd to last sentence...
Please explain how little scratches turn into big ones. Surely you don't believe they grow do you? If anything, small scratches are LESS likely to "lead to" big ones, as it would require a deeper scratch being made precisely where the old small one was.
I was evaluating my brothers "flawless" 5S for him before we sold it, and while it was immaculate, there were micro scratches on the screen. You have to hold it at a certain angle, and look very carefully (sunlight helps too), but they're there.
He was quite upset lol. It is what it is though... no matter how careful you are.
If you used your phone for a year, you have them too. Sorry to break it to ya. As the person I quoted stated:
Just because you don't see them, doesn't mean they aren't there