Maybe someone wants to contribute with a nice post about TeXMacs:
https://news.ycombinator.com/item?id=31491303
Edit: I have contributed with several. People express dissatisfaction about LaTeX and it is a good occasion to let them know that there is a tool that they might like more.
I would be interested in knowing how someone who cares about TeX/LaTeX has managed to not know about TeXmacs.
I have some ideas 
Apart from that, I think that a systematic promotion of TeXmacs will help—so following up on the “systematic” I posted here once that I found a Hacker News thread which I thought people might write on. Posts from different people show that “different people” appreciate the software and this may be more convincing than “posts from one person”.
Edit: of course sensibly argued posts, replica posts are probably less effective
Thanks for the link. I posted some comments. In particular, one about writing in TeXmacs and then converting to LaTeX. It worked quite well (not perfect) and I think such a workflow could ease adoption of TeXmacs: people would not feel that they are “ditching” LaTeX completely and they would be safe in thinking that there is a way to go back to the old, more familiar, workflow. Having the fallback option of going back to LaTeX was surely something that helped me: I started by exporting to LaTeX some notes I tried writing in TeXmacs. It worked so I was not concerned about the transition.
Of course, ultimately, I decided to stick to TeXmacs I mostly do not convert my work to LaTeX. However, for initial adoption I think it is reassuring to be able to convert back and forth.
P.S. BTW, I believe I should note some of the issues I had with the conversion and file bug-reports / questions about it. Will do so shortly
The conversion from LaTeX will never be guaranteed due to the complications of TeX syntax.
There are various bugs about converting to LaTeX: https://savannah.gnu.org/search/?words=LaTeX&type_of_search=bugs&Search=Search