DDG has it’s own community. It’s growing, but I don’t think it will catch up with google. There are other factors too.

As for authenticity. I think people interpret DDG as unwanted, unfortunately. Because it was frequently set as home page as a bundle. If you search its name, you will find people frequently asking “is it a virus”.

It’s hard to advertise an engine these days without being viewed as a forced advertising. But there are better tactics like offering incentives.