Acquiring DDG wouldn't give them much of a head start as its value is mostly anonymizing Bing searches. Apple could just work out a deal directly with Microsoft instead.
They'd acquire DDG if they wanted a jump start into creating their own search technology. DDG does have a DuckDuckBot crawler & obviously lots of staff & expertise in the area (Apple more acqui-hires than anything else). I don't know of a more appropriate Search company they could acquire to give them a headstart given Bing isn't for sale & MSFT is non acquirable.
If Google did decide to drop the payment they'd most definitely turn & collect placement checks from Bing as their first recourse, but if they wanted to build their own search technology they wouldn't be sourcing their results from Bing, they'd want to make sure they're masters of their own fate and own (or license) the technology & expertise themselves like they're doing with Apple Maps.
But I don't see any of this happening, the placement payments benefits both Companies.
