It changed, but not gradually: it was due to new (IMO populist) legislation (that owner-operated shops are exempt from). IIRC the stated goal of the legislation was to stave off replacement of small stores with chains.
IIUC currently the whole situation is a loophole-exploiting arms race. For example, post offices (for some value of) are exempt from that law, so a popular grocery store chain started embedding tiny post offices in their stores[1]. That loophole got closed, and I don't know what they're trying to do now.
[1] Prima facie it's not very weird to do so: it was common practice since decades for the post to contract out operation of a tiny office (that you can use to send/receive registered mail, send money from, and not much more) to a store.
