While that cost is certainly egregiously high, I think you guys don’t realize there is a whole industry around this and that costs are frequently very high due to a host of specific issues surrounding the legal review process.
It’s not so simple as you think. Emails can easily be dumped from exchange or lotus notes, sure… but then they have to be loaded into some sort of application that will process the email data (including attachments) into a format that can be assigned to a squadron of lawyers who need to review and redact the files. Before they can start, the data has to have text extracted and indexed for searching, and any files that need redactions applied need to be converted to a safe format for doing so (TIFF or pdf, usually). There are specialized electronic discovery systems and services that do all of this stuff, but they tend to be very expensive.
Of course the real cost here is the specialized needs of the legal profession, which if you think about it, is always very high. If they simply wanted to dump the emails directly, sure, that’s easy. Getting them all reviewed and redacted in time, that’s a pain in the ass and companies routinely pay millions of dollars for that.