I think Google was withholding them unless Apple was willing to put the ads in.

Apple is a very VERY different company than they were back then.

Back then they didn’t have all sorts of services that they advertised to you constantly. They didn’t have search ads in the App Store. They weren’t trying to squeeze every penny out of every customer all the time no matter how annoying.

Google Search also has ads in it, but that didn't stop Apple from keeping it as the default, and now Apple is adding ads to Apple Maps. GP is correct. Google withheld turn by turn navigation from the iOS app. There are many deficiencies in the iOS platform, but this one was glaringly visible, forcing Apple's hand.