Coming from a wet lab background, I am amused that there's a consensus that current journal publications do not enable the sharing of data in an easily accessible manner.
At the dawn of molecular biology, where cloning a single gene warrants a publication in JBC, sharing is well, rare. :-)
Short of a few labs, I think few labs will readily share their cloned transcripts, cell lines or antibodies.
Part of the reason is of course logistics, which may include lengthy MTA discussions with the university or perhaps it might represent problems with customs with different countries.
There's of course the selfish (gene) hypothesis. If you have ongoing research, it's natural to not want another lab to have a head start to catch up with your post grad student who has been slogging to get his/her publication out.
But I think that it's great that we are all moving towards an era of open science, both in publishing in readily accessible journals and openly sharing data and looking for open collaborations.
It's quite awkward to have competition for publicly funded science, as it seems to suggest we have ran out of interesting questions to ask of the world.
if someone sees a potential for my data, that I overlooked, I will be most happy if something came out of that same data. Because sharing is caring :-)