Presumably that is because you're outside Google's filter bubble, which is kind of the whole point of DuckDuckGo and Startpage et al. Google's results for you

Presumably that is because you're outside Google's filter bubble, which is kind of the whole point of DuckDuckGo and Startpage et al. Google's results for you are better for you because Google knows too much about you. A tradeoff for privacy is less relevant search results, or as I like to think of it, access to pages that Google was hiding from me.