It's important to distinguish between the semantic web and semantic HTML. They are different things.

The criticisms this article levies about the semantic web are pretty much straight on as far as I can tell.

Semantic HTML is pretty straightforward though - it's using HTML to describe content, rather than purely for layout. Some sites do it better than others, but it's certainly not dead or abnormal -- and many static HTML generators are... decent.. ish. Semantic HTML is using stuff like article tags and sections, using actual links instead of just putting a click handler on a div, stuff like that. The stuff that makes it easy to parse and understand a web page.

It's very useful - semantic HTML is the reason that sites like Pocket work, it's the reason why reader mode in Firefox/Safari works. It's the reason why screenreaders on the web work so much better than on native apps (at least as far as my experience on Linux has gone, maybe other people have better apps than me :)) It also (opinion me) makes styling easier, because light descriptive DOM structures tend to be easier to manipulate in CSS than large ones.

The semantic web, to the extent that it's well-defined at all is more about the metadata associated with a webpage. Very different concepts.

There used to be a plugin for Firefox that would indicate if a page contained any FOAF info.