I could easily produce all the bait minnows needed on my property (I have thousands of fathead minnow fry in one right now that I don't even have to feed), but being open long hours of the day doesn't appeal to me. And bait stores don't make their money on bait itself. We have a couple of Amish bait stores in my area that go by the honor system of self serve, but I know one of them got cleaned out of cash one day by somebody.
I had friends that opened a bait store in Avilla years ago and quickly found out it wasn't the panacea they thought it was.