Dynalist is a far more unique value proposition than Obsidian. There are only a handful of usable, maintained, cross platform, cross device outliners & Dynalist is the best by far. Roam may have a grander vision, but their usability & rate of progress particularly on mobile leaves a lot to be desired.
Obsidian is a personal wiki and is potentially in competition with everything from Zim, Tomboy & TiddlyWiki, though org-roam & org-mode to full wiki engines like Gollum, Wiki.js, Dokuwiki, & MediaWiki, or anything else on listed on https://www.wikimatrix.org, https://en.wikipedia.org/wiki/List_of_wiki_software & https://en.wikipedia.org/wiki/Comparison_of_wiki_software, Even the restriction to self hosted, flat file, markdown based wikis leaves a pretty long list. It hard to see a business model in this space. I really like wikis, but my needs for those are already covered. If Dynalist went away I would really feel it.
Dynalist’s biggest shortcoming seems to be lack of marketing: Medium, podcasts, Youtube, … It would be sad to see it derailed.