I clicked hoping the w3c mastodon site would have HTML. But nope, just another mastodon v3+ that only does anything if you run javascript. The w3c should try to do better. It wasn't possible with twitter but it is with mastodon.
Although it should be possible to whip up a text-friendly view of a server you're not logged into assuming they allow non-authenticated access to the API.
Unfortunately /embed is not very useful.
So, I think there's potential, but it's definitely not ideal.
[1] https://fedidb.org/software [2] https://fedidb.org/software/smithereen [3] https://friends.grishka.me/w3c@w3c.social
But sarcasm aside, JS is a web standard, just like HTML and CSS. While I understand the opinion of people who don't want to execute JS in their browser, I'm also highly sympathetic to devs who want to use things that are enabled by default in all modern browsers.
... and this is neither.
And in any case, graceful degradation is a good thing to shoot for, but far from a requirement. Mastodon is Free Software. If someone wants to fork it and make a version that replaces frontend JS with server side rendering, that's legal and fine.