There are only two [general purpose, global] search engines in the world right now: Google and Bing.
And of the two Google is clearly superior. I suspect most people would use it even if Bing was the default.
That contradicts what I find on Wikipedia.
DuckDuckGo's results are a compilation of "over 400" sources, including Yahoo! Search BOSS; Wikipedia; Wolfram Alpha; Bing; its own Web crawler (the DuckDuckBot); and others. It also uses data from crowdsourced sites, including Wikipedia, to populate "Zero-click Info" boxes – grey boxes above the results that display topic summaries and related topics.
I suspect that they initially attempted to do this, but as far as I know these days it's basically Bing. Maybe with a small amount of other sources mixed in.
I'd imagine legal ramifications for Apple but I do think Apple has options that keep Google paying billions.