Elsevier are no doubt scum but I think that scientists share the blame. They all want to be published in the big famous journals. Which gives Elsevier the power to dictate terms.
Of course they want to get published in the big famous journals; the ones that don't lost their funding, and thus aren't scientists any more.
(Which is not to say that some aren't to blame; in particular, the ones on funding committees that still assign value to the journal/publisher names rather than the actual work produced by applicants.)
