I really don't understand how Word remains so popular. It was created at a time when few people had internet access, and was designed to produce printed documents. It was the perfect tool to write newsletters, flyers, articles, academic papers and manuscripts. The world has moved on though, and I fail to see Word's relevance today, other than the sheer number of people that are familiar with it. Word is expensive, pr…
Markdown -- standard markdown isn't expressive enough (no tables for example), there are lots of extensions but none which are "standard".
LaTeX -- doesn't produce accessible documents, so is a non-starter in lots of areas (seriously, the PDFs it generates are some of the worst around when it comes to accessibility. Word's are amazing).