Ill break the seal on your thread, but not with a solution. yes this is pretty common, I started seeing this last november with a ton of sites., now just with a few, but still annoying.
I have Cache's back to Jan 2005 on some.
I suppose one path, though it may be bad advice, others can decide that, is a the url removal tool followed by a reinclusion request.
Removal tool thread and hazzards
Seems if they arnt sending you any traffic anyhow, this is a way to get them to let go of old pages.
The sites I see it with the pages are almost all not even existing anymore, like a ton of old RSS pages or the previous URL owners pages.