You aren't wrong about how it used to be. Seems builders have discovered the Ks rather recently tho, at leasr in the US. I never saw another custom K ever when I first did one like 10 years ago in Los Angeles. Now im in Austin and I've seen 3 in the past year. I have also been keeping an eagle eye on fb marketplace and CL for Ks because I want to build up another one and the prices I see today are about 2x what they were 2-3 years ago. Yes, there are often Ks that novice builders attempted and got in over their heads, but they still sell for 2-3k when ypu used to get them for around d 1k.
They are def a bit harder to build, but they do seem to be getting more popular. I also see them more often than I used to on amateur cafe builders fb group as well.