Quoted By:
Okay, I can't be the only one thinking of this, BUT... vintage and antique toys that are rare and sell for thousands of dollars today weren't thought of as future relics and treasures back then, and nowadays with TV shows like Pawn Stars and American Pickers popularizing hoarding habits for useless junk, I suppose my sealed action figures from the last 10 - 20 years won't be worth as much in, say... 20 - 30 more years because others very likedly thought of keeping sealed the very same toys that I have and thus, rarity will be pretty much non-existant.
TL;DR: I think holding on to sealed toys today won't make them much more valuable in the future because now it's "cool" to keep toys unopened.