It's only considered a beleif at this point because science has no means of proving it yet.
Give it time... though, like I said.
Might as well yell out your back door for a job than try finding a daemon.
You'd have better luck.
And for the record. Most Neopagans have made up their own little story as to what demons are, especially Wiccans. These things have no reflection on the actual practice of evocation.