I think the wild blueberries are actually bilberries, at least that was the case in Russia. Closely related and in the same genus, but they’re distinct species. Like the wild strawberries no one has figured out how to cultivate them so there are few commercial sources and supply is constrained.

Some of my favorite memories of preschool was gathering bilberries in the forest behind the school. It was essentially like Halloween with kids coming back sick from eating too much sugar.