The book "Do the Work" explained it well: "The amateur tweets. The pro works." People who fit into the Shell Silverstein "I'm so good I don't have to brag" bucket aren't as visible because they're working, not talking about working.
Something fairly consistent I've observed: the popular people you see tweeting and on every podcast are likely not very good at what they're popular for.
Sometimes there's overlap, but it's the exception, not the rule.