Etsy https://www.etsy.com/ is full of shops of people who create things as a hobby, but do try to sell things. There are many hobbyist creators who make a few things and try to sell some of them, at least to recoup costs and maybe even earn a little money. In many cases I suspect they earn about $0.001/hour. As a business, it's terrible; as a hobby, many enjoy it. I think "earning a competitive wage" is a reasonable cutoff for at least being on the road to a "real" business.

hmmm.. if we're going to draw a line between "hobby" and "profession", then that's perhaps the most obvious way to do it.