Well, it DOES say the dwellers of both places are staying in there forever (abada...) However no mentioning of paradise or hell lasting forever...but since paradise apparently has always been there (i think...) it won't perish... But since hell isn't even made yet, it will be made then perish along with it's disbelievers because they will achieve "just punishment" as God promises... So...when hell perishes (if at all) it's dwellers will go with it...since they obviously don't deserve paradise...I think Allah knows best.