MX Boot Question

I bought a brand new pair of Alpinestars Tech 7's in 2011 that have never been worn (didn't even try them on around the house). They are still in the box with tags, the cardboard inserts, and plastic bag around them. They have been climate controlled the entire time. I was planning on getting back into riding, though never did, and stored them away in a closet, with the hopes that I would use them eventually.

I know most boots are stiff when they are first new, though when I attempted to flex them this past weekend, they didn't seem to move much at all. I am wanting to sell them though as I have no use for them. Though I don't want to sell someone a pair of boots that are not in a usable condition.

So my question is, can the plastic and leather that is on the boots go bad / dry out from sitting for too long?