At WP's current size, the chances of finding a random vanity article is minuscule - in fact, the critiques of WP's credibility by outside people have been based on points of factual detail in existing articles on familiar subjects, not on whether an "unencyclopedic" article exists or not (which shouldn't be too surprising, since no one will go looking for them in the first place).
Critics will.
The same critics that doomed wikipedia and claimed britannica will always be better?
Thanks, RN