10 years ago, one of the architects I worked with had an email message that stated "I'm on vacation, and when I return, I will delete all emails I receive during this time. If it's important, then please e-mail me when I return on X." And he meant it. He really did delete everything and didn't bother reading a single e-mail. If something really did need his attention, then people would be motivated to contact him, and if some decision was made without his input, then it didn't matter.
This is what happens when people get 200-300 emails a day, and I don't really know of a better way to deal with it, rather than going through thousands of emails when you return from a 2 week vacation.
200-300 emails per day sounds like you need a better spam filter. If not that, then an assistant or two. No one important enough to get 200 meaningful emails per day should be spending their time reading most of it. Hire a VA and get them to do it for ~10-15 dollars an hour and put a summary on your desk.
This is what happens when people get 200-300 emails a day, and I don't really know of a better way to deal with it, rather than going through thousands of emails when you return from a 2 week vacation.