Opting to the dwemer path would mean a failed absorbiside into a giant robot.
No, they were experimenting with it before hand. Before they constructed Numidium, there are oblique references to the Dwemer learning to be immortal. Hold on while I dig up sources...
First, we've got http://www.imperial-library.info/mwbooks/egg_of_time.shtml, which clearly is not showing a Robot becoming connected to the heart.
Then, from the two accounts of the battle at Red Mountain, we have
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.
An explicit reference to this and Vivec's account is a bit more cirumspect:
Engineer Kagrenac of the Dwemer had discovered the Heart of Lorkhan, and that he had learned how to tap its powers, and was building a new god
It doesn't say "learned how to tap its powers to build a new god" it separates them. Furthermore,
Then Nerevar was carried to us where we waited on the slopes of Red Mountain, and he told us all that had transpired under Red Mountain. What Nerevar had said was that the Dwemer had used special tools to turn their people into immortals and that the Heart of Lorkhan held wondrous powers. [Only later did we hear from others present that Dagoth Ur had thought the Dwemer destroyed, not made immortal. And no one knows for sure what really happened there.]
All that Nerevar knew was that the Dwemer vanished. He wouldn't presume to say that they had made themselves immortal unless either Vivec misspoke or Nerevar was jumping to conclusions about their disappearance.