I don't know the answer to this - you could be right, but just outright questioning that Google's search quality is no better than DDG or Bing and basing it off of a single data point is pretty foolhardy. Your second statement reinforces this point - I've run a lot of Google ads, and they're quite effective. Google ads are very effective at selling things to people.

In the future, when coming up with an opinion about something, I'd encourage you to look at statistics and combine that with your own personal experience. You'll often learn something you didn't know, and come up with a more grounded opinion.