This question is loaded. Google does not index search results of other search providers and it never has, because it would create a really bad and potentially buggy user experience (Click through 10 search results to get the real link (if you don't go in a full loop!))

However if you search "Google Search Alternatives" on Google, it displays a large, pronounced box at the top, declaring "Here are 12 alternatives to escape your reliance on Google for all things search."