word of god has stated that the dwemer (dwarves) were absorbed in the Numidium and became its golden skin. This was no accident, as they desired to transcend into godhood and go back to the very first stroke of Padomay and Anu, and the Numidium would be that vessel for the entire race, no matter where they were (even the ones in Hammerfell were absorbed). This isn't something unknown, as one could piece together this kind of conclusion if one digged extremely deep into the dwemer lore in Morrowind.
Thing is, they succeeded in becoming the Numidium's golden skin. The problem is whether or not the Numidium was a success. We know that it has been used to conquer Summerset Ilse, and because of that, Tiber Septim was the first person ever to have defeated and incorporated Summerset Ilse into a Tamriellic empire. However, obscure texts report that the Numidium's invasion is a constant and ongoing war, despire being destroyed by the Underking. At all points in time, the Numidium is invading Summerset Ilse. Not only that, there were 8 Numidiums at once when the Warp of the West occurred. One for each of the nations, one that may have squished Septim's Agen, one used to allow Mannimarco ascend into godhood and block Arkay, one held by the Blades, and the last one to be destroyed when the Underking rejoined with his soul. With those two examples, it can be surmised that the Numidium has the ability to give the dragon of time the birdy.
However, if the Numidium is still roaming free, this suggest it hasn't gone back in time to the first stroke of Padomay and Anu. Another issue was that it was not immediately operational when Kraganec used the tools on Shor's (Lorkhan) heart. And the most problematic thing, there is still one dwarf alive, Yagrum. However, ol' Yagrum is nothing more than a completely bloated pile of cancer from the Divine Disease, who is partially insane, and lost a lot of his memories. His sanity is only maintained due to Dyviath Fyr's care for the creature, along with his daughters who keep him company.
Arcturian Heresy says this:
But Zurin Arctus was working from incomplete plans. He thinks it is the heart of Lorkhan's body that is needed to power the Numidium.
and
The Numidium, while not the god Tiber Septim and the Dwemer hoped for (the Underking was not exactly Lorkhan, after all)
This suggests that they failed... Ofcourse there lots of theories which vary in small details, and Arcturian Heresy isn't most reliable source from what i've gathered.
I put my own "brain-power" into use.
-Numidium is stated to use dis-creation as it's working method. Which seems to point at Padomay.
+Lorkhan is stated to be more alligned to Sithis than Padomay. Which suggests that he (=he's heart) is more about constant change rather than about Is Not.
=This is at which point Kagrenac hit his hand into pile of dung, instead of reaching Tower, I.
Bah! Me one mundane shameful-picture-of-scholar am wiser than Kagrenac. Who didn't have full support of Dwemer. Well i give author of Arturian Heresy bit gredit, so i didn't do it all by myself.