Well, the database wouldn't contain any results. What it does though is reduce the importance of published claims that have a large number of non-published (probably failed) attempts at showing the same effect.

Ideally you want the literature review section of a paper to include a mention of all these related but unpublished experiments, not just other published results.

Boredom is far from the only bad reason that some journals refuse some submissions. Every person in the chain of publication, and that of peer review, must be assumed at least biased and potentially dishonest. Therefore "science" can never be defined by just one database or journal, or even a fixed set of either. Excluded people must always be free to start their own, and their results judged on the processes that produced them. Otherwise whoever is doing the excluding is not to be trusted as an editor.

I hasten to add that this kind of bias exists among all sides and parties.