Historically there was bootleg liquor to avoid tax, but decent bootleg liquor is a lot harder to make than pot, and therefore easier to keep out of the market, so what you’ve observed makes a lot of sense to me.
A good friend of mine has a nephew that is a drug using ne’er do well. He tried to get him to work in his pest control business, but after pot was legalized the kid decided that it would be easier to make money growing pot. Of course he had no interest or knowledge about how to set up any type of legal marijuana business, but he did start growing and selling marijuana. It is a lot easier to grow pot than navigate through the government regs. All it takes are a few grow lights, gardening soil and some seeds to get started. It turns out that the nephew is making much more money doing that than killing bugs, and he is able to stay stoned all the time too.