I carry no brief for Ruby, and method_missing (and its extensive abuse in early Rails) is a major reason why. If you can find no more recent advocacy for that pattern than this, maybe it's time I took another look at the language in earnest.
It's not even that I can't see how the Rails implementors got there; on the one hand it was very early in the development of the modern web concept and nobody really knew what worked and what didn't yet, and on the other, a more modern pattern would have probably been very slow anyway in those days. Still, the experience left a bad taste that I've found hard to shake.
Rubocop has gotten wide adoption and has standardized a lot of good practices. By default it's awfully strict.
I worked full-time with Ruby for 9 years across several companies and I solemnly swear that I never saw a single person use method_missing or consider it as anything other than a mostly terrible idea.
Never saw it used once, or even considered once, in actual application code.
Generally that was the case with any of those "sharp knives" or "potential footgun" language features. Monkey patching is another good example. Used to be extremely common and even recommended, but now it is extremely frowned-upon and used only with extreme care/desperation in application code.
The "problem" with Ruby is that it has become kind of a monoculture around Rails. Rare to see it used for anything but Rails these days. People who want a fun casual language are using Python because Python has that booming ML-adjacent ecosystem and a strong foothold in academia/science.