No,I don't believe that because musing.io is interlink with steemit . If the person join on steemit than only he will able to login on musing.io. So,we cannot say that musing will have more users then steemit.
We can see a people who joined in steemit are only for getting upvotes with the help of musing.we can see people activeness on musing rather then steemit. In musing people have to write answer and besides this they got upvote so instead of writing blogs on steemit people will write answer on musing and they get upvotes and the upvotes are generated in steemit account.