Steemit is probably the first ever blockchain based social media that became successful, but didn't hear any other prominent names after that! But Steemit is not a full fledged Social Media platform like FB.
I consider success basing on the results of the project. And the quality of top rated content from Steemit is absolute garbage. On any other platform even the shittiest bloggers are making much more money than they could make on steemit.
I don't think your statement needs contradiction, not at least from me! However, the focus of Steemit is not to create great content, rather to create money for the users which initially made them very popular! People who have joined Steemit in their initial days, made unbelievable amount of money but with time, their reward has come down because the number of contents went up!
Having said that, we also need to agree on the fact that, steemit is the pioneer of the content rewarding platforms and widely popular compared to any other similar platform running on blockchain!