Thanks, very kind offer. When people paid real money for this, were they paying to make diagrams look good, or for convenient source-editing and rendering in the page? Line9 is built around the first and doesn't have an ideal solution for the second yet.
I think the main thing people paid for was avoidance of change. Devs already use mermaid (by preference or policy) and therefore they wanted to keep using it. When I first build the Markdown Macro in 2012/2013 my thesis was that people would want to keep using Markdown in place of WYSIWIG, and that there was value to having a file in git be a source of truth and updating it there would keep Confluence automatically updated thereby reducing work to keep docs accurate. The first half proved true for devs, the second half did not, the stats showed that almost everyone would paste the markdown source into the in Confluence editor. When we added Mermaid, we saw more of the same. I am not sure how much I can say without violating NDAs, but I would encourage anyone working in this space to work to understand the ratio between how often content is authored vs consumed and by whom in each category. The idea that 1% of people author the content for 99% of consumers that we see on the internet does not translate to corporate environments and this has important product implications.