> (When one editor started asking authors to add their raw data after they submitted a paper to his journal, half of them declined and retracted their submissions. This suggests, in the editor’s words, “a possibility that the raw data did not exist from the beginning.”)

I'm not a researcher, but I've interviewed a lot of researchers in the context of data sharing. I'd go out on a limb and attribute this reluctance not to lack of any dataset whatsoever in most cases, but to a feeling of ownership over your "IP", and an instinct to protect it. In a niche scientific domain, it's not totally paranoid to worry that you could be giving your data to the competition. I heard this again and again, though mostly it was everyone else who did it, not the interview subject...

There's also just the work involved in getting the data in shape to send to people, which can be a pain in the butt.