Your example does not align with your closing statement. Using Arc is certainly not "sticking to web standards" in the way you're proposing.

HN is simple and works, from a user perspective. I don't have my hands on the codebase, but I imagine it's kind of fun to work on precisely because it isn't "close to the metal". DX is just as important as UX is, you have to strike a balance.

Not sure there's much correlation between frameworks and apps becoming complicated or losing touch with their userbase. Using AdWords as an example, I'm like ~75% sure they went from one framework (Google Web Toolkit) to another (AngularJS).