I assumed that every one of those stores were experiments or at least test jigs, and closing or opening them means nothing to anyone outside Amazon.

NYC is a tough market because there is so much competition. But if you're not trying to make money yet you can learn a lot. Perhaps they learnt that New Yorkers don't have the patience to install an app. You generally don't wait that long in a bodega -- I expect to wait longer inside a gas station on the Interstate!