Good HTML output for TeX does exist in various shapes and forms, and in fact Pandoc is one of the weaker converters out there in therms of TeX coverage.

You would get better mileage with tools such as LaTeXML[1] or TeX4HT[2], which cover very substantial subsets of TeX, if not yet 100% feature-complete.

My own take on "Should LaTeX survive on the web?" is "yes, if it evolves to meet the paradigm shift". I wrote a detailed version of that position at [3].

- [1] https://en.wikipedia.org/wiki/LaTeXML

- [2] https://en.wikipedia.org/wiki/TeX4ht

- [3] http://prodg.org/blog/latex_today/2015-03-16/LaTeX%20is%20De...