It's the classic "internet as a means to share information" versus "internet as a means to make money" distinction.
Clear, correct, semantic HTML is important to people who want information to be shared as effectively as possible, who want collecting and processing information to be done easily, and who value correctness.
People trying to make a product don't give a rat's ass about correctness. They don't care if the button is actually a span with some weird inline CSS rules, they just want the blue "buy now" button to be front and center.
Semantic CSS is correct and it's the theory behind web browsing, but priorities have shifted. The web has moved away as a method to share information and has become a method for making apps and interactive experiences. There's no business incentive for correct HTML and CSS, only for the buttons that make money to render correctly.
Aren't there inherent advantages to correct and semantic code, advantages like performance, simplicity, understandability, expressivity, that could/should benefit the business?
Those advantages don't appear on metrics and therefore don't exist. If the benefit to the business is in two years and isn't measurable, the benefit it would bring will be misattributed to whoever happens to be around afterwards using it
That depends on context though. Sure, in a company driving for profits those metrics almost certainly won't exist. If the project is focused on end user experience, though, they would.
Accessibility is one area I've seen an overlap. It is still rare, but I have been on a couple teams where accessibility was a metric and it largely lead to better DOM structure and semantic HTML.
Quite true, unfortunately. But I think there are benefits that can be "feeled" almost instantly. I think problem is one of focus.
Lots of team leads don't focus on these solutions and their benefits but rather on the most recent technologies and their own benefits while ignoring (or accepting as inevitable) their costs. The longer you look in that direction, the harder it gets to see what you are missing or could get by looking elsewhere.
Clear, correct, semantic HTML is important to people who want information to be shared as effectively as possible, who want collecting and processing information to be done easily, and who value correctness.
People trying to make a product don't give a rat's ass about correctness. They don't care if the button is actually a span with some weird inline CSS rules, they just want the blue "buy now" button to be front and center.
Semantic CSS is correct and it's the theory behind web browsing, but priorities have shifted. The web has moved away as a method to share information and has become a method for making apps and interactive experiences. There's no business incentive for correct HTML and CSS, only for the buttons that make money to render correctly.