This might be why Apple rationalizes getting in to the search business. It could be a privacy initiative. That and it may make them more than the billions Google is paying them. As long as they still allow you to pick a search engine, I would be fine with it. I would just worry that Apple might take search ads too far. It is possible Apples privacy principles would keep it from becoming another Google Search in all the worst ways, but I used to think that Apple’s brand value would keep it from tarnishing the App Store with ads… If Apple does create a search engine, I hope it will lead to searching effectively with Siri.
Time will tell what happens but money/profits will come first, otherwise they could've easily chosen a different search engine as the default in order to make a pretty significant privacy statement.