I've been writing code (and prose) with 3 vertical rulers for almost 10 years now: 66, 80 and 120 characters each. None of them are hard limits for me. But they do help guide my eye.
Most lines fit under 66. A lot more than 50%, even code written by other people. I'd say most lines also fit under 80, and very rarely do lines actually cross 120.
I agree hard limits aren't usually a good idea. Especially because they complicate auto-formatting (the Prettier algorithm which is clearly the best doesn't support them). Also sometimes you want to paste a long URL and that's a pain with hard limits.
Most lines fit under 66. A lot more than 50%, even code written by other people. I'd say most lines also fit under 80, and very rarely do lines actually cross 120.