So as usual i was reading books in game (i do that sometimes if i find one with interesting title) and i run into this little gem:http://elderscrolls.wikia.com/wiki/Nerevar_at_Red_Mountain, the following paragraphs seem particularly interesting "Until Dagoth-Ur arrived. House Dagoth had discovered the source of the profane and secret power of the Dwemer: the legendary Heart of Lorkhan, which Dumac's people had used to make themselves immortal and beyond the measure of the gods. In fact, one of the their high priests, Kagrenac, was building a New God so that the Dwemer could claim Resdayn for their own." and "He went to his dying lord Nerevar and asked him what to do with these tools. And Nerevar summoned Azura again, and she showed them how to use the tools to separate the power of the Heart from the Dwemer people."
Now there has been much speculation over the years as to what happened to the Dwemer, from them ascending to another plane, to being bound in Numidium, getting lost in Oblivion etc, but i think truth is much more mundane, Dwemer used Heart of Lorkan to make themselves virtually immortal, but this did not prevent impact of time on them, only staved it off, ad as a result of this perceived immortality they stopped procreating (no need to make new Dwemer when the ones you have will stay around forever) and they probably lived like this for a significant amount of time (several lifespans perhaps) , when Nerevar and Dagoth Ur infiltrated Dwemer capital they found a way to separate the Dwemer from this power, at which point all Dwemer everywhere went back to the way they would be had they not become immortal, simply put they all died and decomposed in seconds since the only thing that kept them alive was the Herat of Lorkan, the one surviving Dwemer has Corprus who's known side-affect is immortality, so in essence the only thing that kept him from decomposing in seconds with the others was his very specific condition.