Do we know how many writers on Substack/Medium/independent blogs employ an editor or researcher in some capacity? I've only seen occasional mention, e.g., Kevin

Do we know how many writers on Substack/Medium/independent blogs employ an editor or researcher in some capacity? I've only seen occasional mention, e.g., Kevin Kelly has said that he employs a librarian as a full time researcher. But the absence of mention isn't necessarily a strong indicator to the negative.