Google was moving to vector rendering instead of static images for Google Maps, which uses a lot less data, so Apple wanted that. Google in turn wanted a lot more data from Apple about the user making the map requests. Apple didn't want to give Google more user data, and Google would't give Apple the better map product without it.
So Apple pushed ahead with their own maps instead, hoping that they'd be good enough to keep people from wanting Google Maps, which ... didn't pan out. Instead, Apple was forced to allow Google Maps in the app store, since their own maps weren't good enough, and people were complaining. So in the end, Google got the data, since lots of people use Google Maps instead of Apple's maps.
And in the long run it worked out fine. Apple Maps is a totally adequate product today despite being inferior to Google Maps for many years. Now we at least have some choice!
I mean, forcing Apple to allow a choice absolutely worked out for people. Apple Maps is decent, but I still generally prefer Google Maps. But iirc they both added my #1 desired feature, which is showing where traffic lights are.
So Apple pushed ahead with their own maps instead, hoping that they'd be good enough to keep people from wanting Google Maps, which ... didn't pan out. Instead, Apple was forced to allow Google Maps in the app store, since their own maps weren't good enough, and people were complaining. So in the end, Google got the data, since lots of people use Google Maps instead of Apple's maps.