There's no payoff for me as a developer to make my website 'semantic'. The only semantic part of my websites is 'robots.txt'.

A nice step forward would be by giving me a way to separate data & presentation. E.g. when a user navigates to list page 2, let me send only the data and reuse the layout html like how we can do with css.

Now, I also happen to consider the Semantic Web to be a delusion that sufficient semantic information can achieve strong AI. I may be wrong, but not any time soon. :)

(edits)