I don't want to dismiss the hard work that people are doing to make the web platform more cohesive. And of course competing interests and priorities will always make the web "lumpy": https://paul.kinlan.me/the-lumpy-web/
But still, as a web developer, it's exhausting. This site doesn't even cover @font-face, ARIA IDref, submit buttons in forms, focus libraries, browser extensions, styling… the list goes on and on. When you work with shadow DOM, you're opting into pain.