Self-hosted blogging had passed on the format of ad-hoc notes while on the move, and basically ignored the entire category of mobile content creation.
It’s odd and sad to see that the desktop-first authoring trend is actually getting re-enforced these days in indie blogging community, as the tools are getting less and less mobile-friendly (another git-driven file-based Markdown static site generator, anyone?)
"Blog" originally stood for "web log", and as such didn't put any constraints or expectations on the media format, length, or quality. At some point format-specific platforms came in, artificially fragmented self-publishing into "microblogging", "photoblogging", "videoblogging", and took it over.
Not everything has to be a well written article, but blogging relinquished "just thinking out loud" type of publishing to mobile-first social networking walled gardens, and it's a real shame and a loss.
Shift to mobile is a massive contributor. Many newcomers to the internet are mobile first, and either don't have permanent access to desktop computers at all, or just couldn't be bothered.
And I don't see many blogging platforms that take this audience seriously. Wordpress seems to be the only one that has a mobile app at all.
Tumblr has a great mobile app — as I said in my initial post, it was actually on top of the mobile trend — but none of the other blogging platforms do. They assume a response web page will work and it won’t — or that you’ll be creating a new file and kicking of a CI/CD build pipeline for a static site — which still doesn’t help if you just want to write an update or post a photo from your phone.
Even easy web builders like Squarespace and Wix and the like have, frankly, subpar mobile options.
You can’t blame people for just deciding to use Facebook or Instagram.