Well, they still need a search provider, a lot of people would change it to Google anyway. Arguably locking down the browser to limit tracking as much as possible is reasonable even though it potentially makes that Google deal less lucrative.
If they were intent on monetising users data, you’d expect them to make a deal with Google to allow tracking in Safari in exchange for a higher fee for default search.
In other words they don’t seem to be doing any of the things We would expect to see if this theory was correct.
But apple (and Android) allowing search providers to bid/buy that default spot is a barrier to entry for new search providers and only makes the dominant search provider stronger. How could a new Google emerge today when people lazily accept the default? When Google started there was not built in browser default - users had to manually type in altavista.com or google.com.
A big company like Coca Cola being able to buy huge advertising campaigns is a barrier to entry for new Cola makers. I suppose there are cases where buying or selling placement might be unethical, but I don't see it here. For example for a long time Google funded Firefox by buying a place as the search default. Was that unethical by Mozilla?
If they were intent on monetising users data, you’d expect them to make a deal with Google to allow tracking in Safari in exchange for a higher fee for default search.
In other words they don’t seem to be doing any of the things We would expect to see if this theory was correct.