[thecatspajamas]

I think that, coupled with the irreversible nature of lamination. Collectors don't like to be locked into previous owners' storage/display preferences. Photos are removed from or placed in frames, matting colors changed, items are broken out of or placed into slabs, taken out of toploaders and placed in sleeves, etc. Even if the laminate itself is in good condition and crystal clear, it's a preservation/display choice made by a previous owner that can't be altered (at least, not without professional restoration, which comes at great expense).

Also, I'm wondering if the laminate affects the ability to authenticate a signature, the same way as being in a plastic sleeve or framed under glass would? I'll leave that to others more knowledgable than I to touch on.