If they had enough power,they could have created more rings,and Sauron couldn't corrupt them (or that's what I think),but the best creator of the rings,Celebrimor,was killed,and the knowledge of forging the Great Rings was gone.It says that Three were made by Celebrimor himself without anyone else.So,when Sauron killed him the knowledge was gone.Sauron maybe had some knowledge about it,but not enough to forge new Rings and the Noldo wich helped Celebrimor most likely sailed to Valinor.
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