So, I originally posted this last year. When I posted it, I was using tectonic as my LaTeX compiler, and since it didn't support HTML output yet, I didn't actually try the article's suggestion.
Today, when I saw that I got an invitation to repost this article from the mods, I thought I'd take the time to try it out.
The two commands that the article suggests can be combined into one:
latexmlpost --dest=mydoc.html --format=html5 <(latexml mydoc.tex)
I did a comparison[1] of pdflatex and latexml using some old assignments, and it looks like compiling to HTML isn't fully there yet: the spacing was off in some places, and manual line breaks didn't work. But, I remain hopeful. If this gets polished, viewing LaTeX documents on phones would be much nicer.