At one point I was working on a POS proof of concept that would offer the software for free to restaurants to use with the caveat that we could sell their anonymized patron data as reports to restaurateurs looking to gather intel on viability of new restaurant locations. I got bored of it and stopped before I validated the market for it, but I think there is space for this. This was before vendors like square had their products for small businesses, however. At the time, my potential competitors were the NCR Aloha's of the world.

Yeah, wherever there's money, there's valuable information.

POS' are a goldmine if you can acquire data from huge numbers of them (unfortunately that's hard).

That's definitely true. I would have had to operate at a loss for a while until I could enough data to sell. I never did the math to see how long that period is, but I'm pretty sure it's worse than my back of the napkin calculations.

I worked at a fast food place that has that capability in 1994. It could correlate patterns for upsells.

Iirc it was an NCR XT based system.