I recently took a pair of quite old Ecco shoes from storage and found out that the soles had become soft and sticky, rendering the shoes unusable.
I almost threw the shoes away already, but then I started thinking if there would be any way to fix the soles. Definitely last pair of Ecco shoes I will ever buy, this expensive shoes should last longer at least when not used at all! And you know, at least I've paid my dues now, I now know about this material and it's "special needs".
Also, shoes are meant to be worn and not forgotten to your parents storage closet for years. I don't know anything about rubber, vulcanization or that kinds of stuff, but I thought that what if I would put the shoes to oven for example? Seems that the material is not rubber, but injection molded polyurethane and it does hydrolyze when stored long periods of time.