I think a lot of people here are ignoring the self-imposed limitations on production. There are deadlines for books, there is a hard limitation to how many pages there can be, etc etc. This isn't like the third parties where we can do whatever we want and make a book of whatever page count due to KS; even though WotC has the funds to make 400-page god-like bangers with top-tier art, playtested content, and professional prose, they won't because that's not the cheapest way to create a book that'll sell.
First-party is essentially an exercise in minimalism and fluff. I'm personally ok with this, even though it might sound like I'm not. Now, could the content inside the books still be better? Yes. Look at the OSR, Free League, etc etc, just so many. But with competing internal visions of the game, a minimal playtest process, a tight turnaround, and Unearthed Arcana being a requirement for anything mechanically significant, it's unlikely WotC will ever produce truly 10/10 RPG books.