I think I'd say "common-place" i.e. plenty don't wear them (more so in some niches/activities than others, of course).
[Edit: halfway through typing, I forgot that djb is in Canada! Apologies. My post is about the UK.]
During the pandemic - which of course saw an initial huge surge in leisure cycling - I think I've seen a plateauing in public "pro-helmet" opinion. Now on platforms like twitter it's normal to hear folks annoyed by helmet-shaming. If a motorist criticises non-lid wearers, you now get
MORE people promoting CHOICE
than throwing insults at "idiots who don't care about their brains" etc etc ...
And it's been a while since a random stranger ranted about my bare head.
SORRY THREAD DIVERSION - but HE STARTED IT SIR, NOT ME!!!