The big difference is that Apple does not have the incentive to collect user data in the first place. This is why Apple's ML strategy has tended to lean towards on device, while Googles has been in the cloud. Apple has taken the stance that the best way to keep a users data safe is to never have access at all.

Google aggregates all its data points about me and sells that as a service to advertisers. It makes sense. Advertisers want to pay for ads that will lead to sales.

Yes Apple sells ads on its AppStore and allows ads in apps. But what they sell is the chance to be in front of a billion affluent iOS owners which is different than using every bit of data from every Google property to create a profile of a user so as to target ads even more effectively or show you even more extreme videos to keep you ever more engaged a la YouTube.