agreed, and they along with whether I personally like the product go into my evaluation of quality. Since nothing about the ones you listed changed in the last 10 years, guess which one affects the result...
But, you're not actually evaluating quality. You're evaluating whether you like something or not. Which, again, there's absolutely nothing wrong with that. Advocate for what you love. Absolutely. But, pretending that your evaluation has anything to do with quality dilutes the term and renders it meaningless.
You're judging something based on whether or not it appeals to you and you can articulate why it appeals to you. Fantastic. That's great. Zero problems with that.
But, then you're taking a step further and claiming that just because it appeals to you, it becomes something that is objectively better than something you don't like, not because of any qualitative difference but, simply because of your personal preference. That's the problem I have here.
It is objectively true that WotC has set the standard for quality for RPG books for years. I remember the days of black and white softcover books. I remember the days of 6 point type on brown paper (looking at you Dungeon Magazine). I remember the days of stream of consciousness writing in adventures that made it really difficult to run those adventures at the table because information was buried three paragraphs down from where it should have been.
Hell, indexes. There's something of very poor quality in the PHB. The index in the 5e PHB is garbage.
But claims of a peak in quality? That's ludicrous. Like you said, it hasn't changed in 10 years. Or, if anything, it's generally gotten better.