the edits spurred the rant about had this field set already - ie Doepfer stuff. A quick search yields that 24 or 37 with the word discontinued in it, have this field set.
I agree it's a community effort. That's the point, really. There is quite a bit of effort to be had without people added to the the pile. (duplicate entries, incomplete entries, person modules not marked as private, etc).
I personally updated the field on 250+ modules. There are some that are manufacturer locked but generally the major manufacturer stuff is marked properly.