I've met plenty. Interviewed 6 candidates a few years ago - only one even brought anything beyond his resume. He brought a full physical portfolio of work he'd done. Most of it was web screenshots and such - not much 'code' to speak of, but he'd made the effort. No one else did.

I've been in plenty of places where people say "I can't show my work, cause it's for my previous employer". And they don't code when they go home. Or on weekends.

I brought code samples to an interview once, and the interviewer wouldn't look at it because "it wouldn't be fair to other people who don't bring code samples".

No doubt many people can, but you may be living in a bit of a self-selection bubble where everyone you know and mix with has loads of spare code to demonstrate. Many people don't. Now... if you want to use that as a signal for that person's interest level or ability, feel free to. You may be missing out on some otherwise competent or talented folks. But we all have to use signals to filter out candidates, and that may be a valid signal for you to use.