It's not that I've not been drawing every day. But my marriage is more important than drawing every day, and my job is more important than my posting every day, and just from the perspective of posting, while we're on that subject, site maintenance is more important than all of that, since I couldn't post.
However, taking a shotgun to all of my plugins (except the Classic Editor, which WordPress Gutenberg can pry out of my COLD DEAD HANDS) and running all available updates got the site back to life. Still not sure what precisely went wrong here, as the failure wasn't correlated with any detectable change.
SO anyway, drawing hasn't stopped, but posting of them will resume when I get the huge box of stereo wires detangled so the site is smooth again. Pictured: me, having a drink with my wife, spending a wonderful afternoon and evening together, most of which did NOT involve any form of drawing.
UPDATE: The problem was the Jetpack plugin, and it persists even if the plugin is reinstalled from scratch. This has some precedent, as I see other users with the same problem, though I haven't dug deeply enough to understand what is going on in my case.