There are a number of problems here, so I apologize if my approach seems scattered. I'll start narrow and go broader.
The major substantive issue with this proposal is adeptly pointed about arzke, here: https://news.ycombinator.com/item?id=36616677 Namely, using <br /> instead of <br> is a useful annotation to beginners who haven't fully internalized the rules about self-closing yet; it also, minimally, reduces cognitive load on more experienced developers, just like any other such annotation (e.g., a C comment when you skip fclose() because you're using stdin or stdout). While such annotations have no material affect on the final product, they are indispensable for beginners and externalize bookkeeping, reducing cognitive load even for more seasoned devs.
As a result, there are broader implications: proposals like these make the Web a less-friendly place for beginners. I believe the "old Web" had something valuable that's been lost. The creation of things like NeoCities (and its generally positive reception on HN: https://news.ycombinator.com/item?id=33648618 ) makes me believe that view is widely shared. Proposals that make learning HTML harder, even if only slightly, run counter to these shared values. (While omitting the annotation on self-closing tags is the tiniest of tiny drops in the bucket, so is the bandwidth saved; so while my objection is vulnerable to a criticism that the danger is de minimis, so is the OP position.)
Worst, though, is the strident smugness with which OP dismisses all the criticisms of his position, in his blog comments, in the related Twitter thread, and here on HN. "There's a whole section in the article about the risk to beginners" is only slightly more tactful than RTFA, but it nevertheless assumes the other commenter hasn't read the link (in violation of HN guidelines), and refuses to engage in a discussion on the merits, instead just asking for another hit on the OP's blog post.
Speaking of trolling for blog hits, this post, like all but one of jaffathecake's past 30 submissions, is pure self-promotion, which is obvious when you actually go to jakearchibald.com and see that the Twitter handle there is jaffathecake, and the gmail address there is jaffathecake. "Please don't use HN primarily for promotion. It's ok to post your own stuff part of the time, but the primary use of the site should be for curiosity." https://news.ycombinator.com/newsguidelines.html
I vehemently disagree that HTML needs to be rid of all redundancies on the assumption that anyone reading it already has the rules about which tags are self-closing memorized and internalized. I even more strongly disagree that shameless self-promotion is within the spirit or text of HN's rules.
I disagree with your technical opinion: As an HTML beginner in 1995, I had no problems understanding the tags that contain vs those unable to contain (an image or horizontal rule won't contain a paragraph) and frankly find any extra symbols or markup properties take away legibility. In fact, I recall my biggest confusion was the introduction of div and span, because they both seemed to contain text, and both do something style-related but somehow distinct between the two that I didn't understand at the time.
Furthermore, I'm not a fan of your personal beef with Jake and think it's over the line to accuse self promotion when he's not selling a book or service or anything other than seemingly pushing an opinion.
jaffathecake has posted, on average, once per year for the past two years. Going back to his account beginning: it's five times per year.
He posts topics that are engaging (over 60 points per post for the past 30 posts, only 10 of these posts were ignored) as well as technical and usually interesting. He then has a discussion---there are certainly other blog posters who simply post and leave. I much prefer this largely posting of one's own work to people posting tangentially relevant (at best) articles from Politico or The Atlantic. Other people regularly link his posts, confirming that he has an audience on HN. He's not even reposting his old articles or posting three times in a week when a topic doesn't "catch" on the first two attempts like MANY of the karma-heavy serial posters on HN.
His comment style (aka stubbornness) probably comes from his own development experience and he doesn't see the perspective of people writing simple "gg=G" auto-indent algorithms using Python in a new world of custom HTML elements (web components) or writing regex to quickly add a property like aria-level to every tag that can contain. These might be inefficient and contrived use-cases, and he'd probably have a leg to stand on that the trailing slash isn't necessary in those two cases, and I'd like to see what that response looks like, because I tend to oscillate between using an SSG (which I despise because I find myself picking apart i18n bugs across multiple files---a task I'm doing today) and writing HTML by hand (where I find myself needing to bulk-edit with vim or sed). This---the complexity of most frameworks vs keeping it all in your head while learning why "strong" is now preferred over "b" and trying to hand-write responsive CSS---is the modern reality that is making larger-scale web development more inaccessible for tech-half-savvy folks.
I fail to see that he's selling anything. I don't see ads anywhere on his blog. He even rejects recruiters and advertising offers on his front page. If this whole blog of his is just a ploy to get people onto his other (potentially monetized) social media, he is not pushy about it AT ALL.
The major substantive issue with this proposal is adeptly pointed about arzke, here: https://news.ycombinator.com/item?id=36616677 Namely, using <br /> instead of <br> is a useful annotation to beginners who haven't fully internalized the rules about self-closing yet; it also, minimally, reduces cognitive load on more experienced developers, just like any other such annotation (e.g., a C comment when you skip fclose() because you're using stdin or stdout). While such annotations have no material affect on the final product, they are indispensable for beginners and externalize bookkeeping, reducing cognitive load even for more seasoned devs.
As a result, there are broader implications: proposals like these make the Web a less-friendly place for beginners. I believe the "old Web" had something valuable that's been lost. The creation of things like NeoCities (and its generally positive reception on HN: https://news.ycombinator.com/item?id=33648618 ) makes me believe that view is widely shared. Proposals that make learning HTML harder, even if only slightly, run counter to these shared values. (While omitting the annotation on self-closing tags is the tiniest of tiny drops in the bucket, so is the bandwidth saved; so while my objection is vulnerable to a criticism that the danger is de minimis, so is the OP position.)
Worst, though, is the strident smugness with which OP dismisses all the criticisms of his position, in his blog comments, in the related Twitter thread, and here on HN. "There's a whole section in the article about the risk to beginners" is only slightly more tactful than RTFA, but it nevertheless assumes the other commenter hasn't read the link (in violation of HN guidelines), and refuses to engage in a discussion on the merits, instead just asking for another hit on the OP's blog post.
Speaking of trolling for blog hits, this post, like all but one of jaffathecake's past 30 submissions, is pure self-promotion, which is obvious when you actually go to jakearchibald.com and see that the Twitter handle there is jaffathecake, and the gmail address there is jaffathecake. "Please don't use HN primarily for promotion. It's ok to post your own stuff part of the time, but the primary use of the site should be for curiosity." https://news.ycombinator.com/newsguidelines.html
I vehemently disagree that HTML needs to be rid of all redundancies on the assumption that anyone reading it already has the rules about which tags are self-closing memorized and internalized. I even more strongly disagree that shameless self-promotion is within the spirit or text of HN's rules.