They have been working (very hard) on this for 4 years. If that's a shortcut, what is a long cut?

I would pay a non-trivial amount of money for an app that, amongst other things, told me which coffeeshops in my area has the least traffic.

Just look for Yelp 1-star reviews on coffeeshops. I reckon that should work. I know this sounds like a facetious answer, but any app that does what you asked for would probably return results that correlate with the quality of the coffee.