Cardoons are one of the things on my "bucket list of foods I've never tried", and reading you mention this makes me wonder why they aren't grown in the US. Or if they are, why they don't get distributed?
Food "prevalence" in general is mysterious to me. It seems to me there are a lot of foods that could be more widespread but aren't for historical or quirky reasons. Pawpaws seem to be one of many similar examples.