Also, at least the last time I checked, the Google Maps API was exorbitantly expensive. Niantic would likely get a discount, but avoiding this exploit doesn’t override all of the other benefits of OSM.

IIRC many of the original employees were ex-Googlers and the original Ingress game did use Google Maps data so at some level they were able to get what they need. I think there were rumours about them using undocumented abilities too in the early days, but my memory is fuzzy at this point. They moved to OSM later.