That would be a good idea and I bet a lot of people would buy them and use them. A lot of binders have the slip sheet area where you could slide it into the cover without using the sticker.
I don't think Topps would do it or allow it to be done though because it may take away from the binder sales.
I agree that it probably won't happen. For the small group that is willing to buy the binders, I think they will buy both. This would interest the binder buyers AND many others that won't spend the high price on the binders IMO. I never even thought of putting them in the cover of other binders to "roll my own" wacky binder. That is a good idea also.
I wonder if a group of 10 or 20 people could get together to commission, say, 4 binder collages like the NSU project, in full color & share the printing costs for the specific purpose of creating our own binder artwork. This way we could use the binder sizes & types we are each comfortable with & still have the cool artwork for them.