One only uses Google services if one absolutely needs to. Google on the other hand never needs you. You are absolutely unnecessary and super easy to replace. Whichever you chose, the next search engine really needs our queries. If we give them enough they might be able to create a competitive product. If they do google will dramatically improve. I'm sure they have plenty of ideas, the incentive is just not there.
The other 20% I resort to Google are mostly things with a geographical/country context, which DDG really sucks and Google excels.