Sherry, I'm reading the book "The Daily Stoic." Good stuff.
I think some level of engagement by top writers, particularly in the beginning, can help propel them into the stratosphere. But yes, it goes without saying that there is no need for frequent engagement if you have a lot of eyes on your writing. Nor would it be productive, as it takes away from time spent writing.
I personally think it's a mix--some people are top writers because their writing is that good, and others are top writers because they "network," so to speak, and build a loyal audience, even if their writing isn't the best. I do think subject matter is key for a lot of top writers, though. People genuinely want to read what they're writing because the topic or subject is interesting or intriguing to them. Just a personal observation.