Apple made them the default because they are the best at monetization of large volumes of search queries from iOS devices. If another company was better at it, they'd put in a higher bid and rake in the profits.

> If another company was better at it, they'd put in a higher bid and rake in the profits.

The point is that there is no world in which any other company can outpay Google, regardless of whether or not they are better at search.

I'm not sure if "outpay Google" is necessary for that. Apple and Google are competitors, in some aspects this seemed almost personal (Steve Jobs mentioned "thermonuclear war", see https://www.forbes.com/sites/ewanspence/2015/01/31/how-apple...)

Another search engine that is 90% there and can offer only 10% of payments might have been good enough (at least in a certain time frame) if it gave Apple an opportunity to snub Google.

They aren’t specifically trying to kill other search engines though. They’re just trying to acquire more users, by being the default service.

That makes a strange legal argument, though. You can't say that Apple putting the default up for bid is anti-competitive behavior by Google. So would you say that Google can't bid in the auction because that in itself is anti-competitive? That also seems like a tough legal argument to make (though I am not an expert on this) because it means that basically everybody is allowed to be in the auction except for Google.

You could definitely say it was anti-competitive if Google was paying more than they earned from this search traffic. But I seriously doubt they are doing that.