Sorry for posting a second comment, but this just occurred to me:

Mapbox serves all of its customers’ vector tiles through AWS CloudFront.

Is this a possible case of Amazon seeing Mapbox’s traffic numbers, being able to estimate revenue based on pricing/the number of average tiles loaded per map session, and deciding that it was worth to take a plunge?

(There might have been other factors too but — was this /not/ a factor?)

To be very (... paranoid doesn’t feel like the right word), wouldn’t Amazon also have info in the same way on Mapbox’s largest customers and know who to pursue/target first for their new service?