For a small site maybe, but you underestimate the challenge of some of these things for enterprise sites. If a new directory or slug is added to a site, what team in an organization is going to care if all urls are redirected correctly? For a site with tens of millions of pages, who is going to make sure they're all working the way we want? Who makes sure robots.txt files take into account those changes? Are sitemaps updated for crawlers? Are all our analytics tools in line with the new url structure? etc..
Every large site I've worked on doesn't actively think about these problems, and it's the SEO team who has thought about these problems.
Generally people care about their slice of responsibility. At most large organizations with enterprise sites, many parts of SEO falls outside of those slices of responsibility so people don't think about them. This is especially true if it's hard to put dollar values on them.
They put it after so you scroll past the display ads which are also on the page. If you didn't have to scroll down past the ads those ads wouldn't be monetized
I made another comment above asking about recipes which should answer your Q. But you may be right, copyright could be another component that I'm not aware of. However, SEO is certainly a large part of the reason for long recipe posts as it's definitely going to help get more traffic on average (to our collective detriment).
While Google does seem to use engagement metrics to help with ranks I don't think it's as simple as you laid it out (which is fair you were likely oversimplifying for brevity). Google themselves have said just because you bounce quickly doesn't mean it's a bad result, could mean you found your answer and now you have another question based off of that.
My understanding from case studies I've read and tests I've seen done is 1) engagement metrics seem to be most useful at the top 5 rank positions in the search results 2) it's really hard to measure when improved engagement metrics actually improve ranks.
On the flipside adding content to a page usually results in fairly quick change in ranks and is relatively easy to track. And it makes sense. A normal recipe is a list of ingredients and an order/method to cook them. 100-300 words tops in most cases. Not a lot of info for a bot to understand what the context of the recipe is around.
Now if you spend another 750 words writing about how to do it Google gets a lot more context and reinforcement that what you're talking about is actually relevant. Keyword stuffing isn't a thing in that you can literally say the same word over and over and get higher ranks, but if you can stuff a post with relevant keywords sprinkled all over the place that's good enough for Google to say 'oh now I get what this page is about'.
So there may be some slight impact on engagement metrics (which is debatable since a lot of people find all that long text super annoying and will bounce because of it), it's the extra text/keywords that Google understands and values.
I realize I'm inviting the ire of HN, but I'm an SEO and fully agree with the sentiment of the article. Namely a lot of content on the web is purely for Google.
What some people miss is this isn't just SEOs gaming the system. This is a system that Google explicitly asks for. I've watched John Mueller's (a Google Search Rep) AMA sessions where he answers questions on SEO and he's advocated for webmasters to add text onto product listing pages to "help users" get a clearer understanding of the page. Nope. It's because even though Google has some of the best technology in the world, it's search algo is still pretty dumb.
No person needs a few sentences of text on an ecommerce page about couches to understand the page is relevant to couches and sofas, but Google does because it only understands text. That's also the reason why any recipe you find on the internet is buried at the bottom of the page.
The pointless adding of content to the internet is annoying as hell, but given that ChatGPT is able to create fairly cogent answers for a majority of queries it's, I'm frankly surprised Google isn't better.
Lastly, this article really only references creating content for SEO which is not all of SEO. Many parts of SEO actually do make sense. For example, making sure your content is actually visible onsite, redirecting old urls to new urls, making sure to internally link to pages people actually care about, etc... These should be website best practices but a ton of websites don't do them.
Good SEO is hard. Creating changes that are good for Google + users takes a lot of thought, effort, and testing. Bad SEO (i.e generating a bunch of pages/useless content for Google) is very easy and you don't need to know anything about actual SEO to do it. For some reason anyone able to look up a keywords search volume and write a post is an SEO.