The rest of the world doesn't care about NSA surveillance so 600% doesn't really mean anything and is meaningless. Hell, a lot of people don't even know what Bing is!
http://www.wired.co.uk/news/archive/2015-05/18/gchq-hacking-...
But the early adopters do, and these are the high technologists, the users of HackerNews, and it appears that these are the ones driving the change. The other replies to your comment sadly seem to equate the "rest of the world" as non US early adopters / users on HN.
This may or may not lead to the late adopters coming along to DDG in a few years. If they come, it will not be because of privacy matters, or the bang syntax but because a) it would be better and/or b) everyone else is doing it.