It depends on what you want out of a search engine. Do you want a search that tries to give you what it thinks you want? Or do you want a search that functions more like a library index where you're going to get what you searched for, even if that might ironically not really be exactly what you wanted - so the onus of creating a more correct search term is on you.

This isn't a rhetorical question of course. There are major arguments for both. But I think a pretty good chunk of DDG users were more often after the library index than what ideally would be a librarian recommendation, but in reality is more like a stereotypical used car salesman style recommendation.