Semantic web is data science for the browser. Most people can’t even figure out how to architect HTML/JS without a colossal tool to do it for them, so figuring out data science architecture in the browser is a huge ask.
one that thinks you should use tools to generate HTML/JS and those tools should generate strict XML and any extra semantic data. The problem is that the actual users of these tools either don't care, or know about semantic HTML nor semantic data.
Then the other camp that thinks HTML should be written by hand which makes it small, simple and semantic (layout and design separated into CSS) without any div elements.
Hand-writing the semantic data in addition to the semantic HTML becomes too burdensome.