HTML by contrast explicitly does remove control over layout from the author and place it in the hands of the user (and their chosen user agent).
Both languages have mechanisms to (somewhat) separate the content from the formatting rules.
LaTeX would rather produce a bad document if it cannot produce a good one. Example: overfull hbox. A designer is still required who creates the documentclass, it is just that LaTeX comes with some predefined ones intended for scientific publishing.
HTML+CSS require pixel-perfect rendering. Example: ACID2 test. While it might have been the idea of plain HTML at some point (<em> instead of <i>), control has never been taken away from the author thanks to CSS.
Your comments about LaTeX do not seem to contradict anything I said.
Or are you arguing that there are somehow more people reading printed papers than digital?
But regardless, I think that, in addition to moving away from Latex we should also reconsider the primary output format. Documents are rarely printed anymore, and inaccessible, fixed-size A4 pdfs are annoying to read on anything but an iPad Pro.