So if DDG degraded in quality I'd be fine, because I don't expect perfection. Though I suppose it depends on how much, of course.
DDG used the Yahoo Boss API [0] originally. It was pretty good, but Yahoo shut it down and Bing now also powers their search engine.
In July 2009, Microsoft and Yahoo! announced a deal in which Bing would power Yahoo! Search. All Yahoo! Search global customers and partners made the transition by early 2012. The deal was altered in 2015, meaning Yahoo! was only required to use Bing for a "majority" of searches.
I know for sure people have said DDG is better over time. I can’t imagine it was very good in 2008 or 2009.
Note: I know Yahoo is Bing behind the scene - I'm just saying the technical implementation at the time was not tied exclusively to "bing.com".
2016 is the year Yahoo was sold to Verizon. 2 years later, Verizon writes down $4.6B of the AOL Yahoo subsidiary. A year after that they sell Tumblr in a fire sale. Verizon stopped caring about their web media empire when they did the write down/sale too. Effectively throwing in the towel as a major web advertising hub even though they are likely still top 5 in the west after Google, Facebook, Microsoft, Amazon. That’s peanuts to Verizon though.
I can’t imagine Verizon cares much about their deal with DDG. If Microsoft cared, it makes sense that they could have Verizon and Yahoo do what they want over lawsuit worries from DDG.
I’m being pedantic at this point and totally guessing with my assumptions. I admit the continuous praising of DDG on the web has gotten to me and likely making me feel and react this way.