This article really doesn't get what LaTeX does. Of course it is overkill to have 5 lines of text rendered with LaTeX into a PDF. But the point of LaTeX is exactly to set the typesetting of an output document in stone. PDF is meant to do that and HTML cannot do that. A PDF conserves everything and that is precisely the point to have a set layout for printing or displaying on different devices.

Yes, there should be easy ways to display math on the web. No, this doesn't mean that LaTeX is obsolete.

Besides, what about references, both external and internal? Probably needs more "modern" tooling.