All non-application websites should provide all their content in semantic HTML at appropriate HTTP endpoints, with CSS styling (in as few requests as possible) as required per the design, and JavaScript (in as few requests as possible) that takes the semantic HTML and makes it interactive (potentially adding and removing elements from the DOM) as required per the design. The CSS should not depend on mutations resulting from the JavaScript, nor should the JavaScript assume anything of the applied styles (as the user agent should be able to easily apply custom user-styles for your site; e.g. Gmail only providing a limited set of styles that are managed server-side is laughable).
Thus, all content is readable and styled properly without requiring an arbitrary code execution environment. That is what the web was meant to be. Unfortunately, most "web developers" have made the web worse over the past 10 years because simple, functional, minimal technology is not impressive, and hipsters love to show off.
Nor does it help that there are few capitalist incentives for the web being open and malleable -- e.g. so users can easily use a different front-end for Facebook, or users can easily choose to avoid analytics or advertisements, or users might prefer to use the website rather than the app (providing access to personal details, contacts, location, tracking, etc).
The state of the web is emergent and I'm not sure what anyone could do about it (perhaps make a better browser?), but it really irks me when web developers pretend like they're actually doing something good or useful, or that the web is actually in a healthy state. In my experience, it's the people who don't talk about web development who are the best web developers; these are the people who don't wince when they write a HTML document without a single `<script>`.