Unfortunately, this is also the case for the majority of commercially-published science. And no, JSTOR is not a good response because JSTOR doesn't even begin to scratch the surface of science. Science is one of the most important efforts in human history, and we don't have backups, or even mirrors. Great.
Edit: does anyone know some orgs with deep pockets that would be willing to accept and host 30-50 terabytes of papers? I can't seem to find anyone that doesn't wuss out. I know it's risky, but it's also critically important.