Who says web components are meant for use directly by the developer? Maybe they're primarily meant for the browser developers (those who build browser features), not for use directly by web app developers.
> The World Wide Web Consortium (W3C) develops standards and guidelines to help everyone build a web based on the principles of accessibility, internationalization, privacy and security.
Web Components are a standard to be used by web devs.
Reasons for rejection include a reporting API seen as privacy-invading and related disagreement over whether W3C's HTML WG could augment/redact WHATWG spec text like they used to be doing until 2017 when the previous HTML recommendation was published, or has to go through WHATWG process for any change according to the W3C/WHATWG "memorandum of understanding" which thus hasn't resulted in common understanding after all ;) Another reason was objection against the so-called HTML5 outlining algorithm, which Steve Faulkner actually has gone to great lenghts removing in WHATWG HTML upstream (cf. [2] for details).
Unfortunately, the removal also brought incompatible change to HTML (the content model of hgroup, among other incompatibilities), rendering existing content invalid, which WHATWG set out not to be doing but which they lack the methodology of preventing and for which the spec derived from Ian Hickson's work frankly lacks formal qualities to support. Even more unfortunate is that this change has already spilled to derived standards such as EPUB3 which hence makes existing EPUB3 content using compound headings going back to 2011 invalid, and EPUB3 writers lacking a tool for actually verifying what readers can support (epubcheck was blindly updated without consideration for the installed base). Technically, Review Draft January 2022 and newer should then already be called HTML 6. Since nobody gives a rat's ass (including W3C, Inc.'s dormant HTML WG) anyway, and gross misconceptions about HTML specs prevail, like in your post, I'm not sure whether we should call it a day with WHATWG/W3C's HTML specs already.
[1]: https://www.w3.org/blog/2021/whatwg-review-drafts-of-html-an...
You can't implement stuff efficiently if there's no required functionality in the platform
> Who says web components are meant for use directly by the developer?
The people who develop them
Unfortunately, the trash "become a programmer in three days" bootcamps and scam courses all target web development, flooding the market with people who were taught one or two tricks and told they're the cream of the crop and should definitely not ask for their money back if nobody wants to hire them.
It's the same problem PHP and Python have suffered from: when your programming language and API is accessible and easy to use, you'll attract a lot of beginners and people who skipped the hard parts.
For some reason, the frontend world seems intent on reinventing itself every five years or so. The backend world works in cycles of 10 to 20 years, but it's going through the same motions. Everything became C, then C++ and Delphi came along, then everything became Java and DotNet, mow everything is becoming Go and Rust, and every iteration brings about new design concepts and paradigms.
I believe Wikipedia uses mostly frameworkless Javascript, but, as you might expect from any sufficiently sized project, they have come up with their own frameworks instead.