Wikipedia has book citations, and more and better book citations than traditional encyclopedias.
It's unclear what your point is. Are you suggesting wikipedia shouldn't also have citations to content published online, simply because it might be removed?
Most wikipedia citations are linked to some news articles (this is not too bad, still newspapers are being archived) and some random internet blog articles of some random people which show up and disappear. Source creditworthness analysis? Good joke Wikipedia says :-) At best you can get some people's opinion about something.
And this is cherry picking. As studies show the quality varies strongly for historical, politically controversial and highly scientifical topics ( only few wikipedia editors ). Link https://dl.acm.org/doi/fullHtml/10.1145/3178876.3186132#BibP... So nothing "easily disproven"
It's unclear what your point is. Are you suggesting wikipedia shouldn't also have citations to content published online, simply because it might be removed?