Interesting one if you look at Google Ngram Viewer – usage dropped off massively to 70s/80s, and it's picked back up since but not to 1953 or earlier levels, so even that doesn't explain it.
Must just be the combination of that increase as well as other words decreasing in usage I suppose. E.g. perhaps we're a bit less keen, but also much less passionate, so keen ends up making the cut.
As a native English speaker, keen feels like a very 1950s TV word. Don't know if that's actually true but feels like that way. I expect you're more likely to hear like cool today are some more contemporary word.
It's still used in a couple of specific senses - it's used in the nearly fixed phrases "keen edge" or "keen mind" as a synonym for "sharp", and as "to be keen to -" to mean "eager". But, in my experience, it's rarely used to mean grieving ("to keen over -"), and almost never as a generic term of approval ("that's real keen").
Keen is definitely a word but when used to describe a person it’s often a bit of a backhanded compliment… you don’t really want to be keen.
Saying "I'm keen to do x" or "he's keen to do y" is a fairly common normal usage but having said that, wouldn't normally be my first choice of language as a millennial, maybe does sound a bit old fashioned
Still in common use in Britain as far as I know. A more local (Bristolian) word would be "keener" used to describe someone who puts lots of effort into a task to win praise.
“It offers fewer words for the people directly around you, but more for belonging at a distance” - the further I get into this article the more it just seems like sampling bias as a narrative.
It's a wordy (/AI?) way to say it, but I took it to be commenting on our lives being more 'abstract'/digital than they were, so naturally a lot of our language is less physical.
Oughtn't really affect emotive language like 'keen', though.
Must just be the combination of that increase as well as other words decreasing in usage I suppose. E.g. perhaps we're a bit less keen, but also much less passionate, so keen ends up making the cut.