they do since Substack was invented because it turns out a digital rehabilitation facility for whiny and overly wordy sore losers is a fantastic subscription business.
Might want to think about selling that one to Disney as well and then writing about your great regrets of selling your substack on substack v2 in ten years, that's gotta be amazing content for another ten posts
What are your criteria for recognizing a useful insightful blog into a poster's previous business ventures?
Few tellers are neutral and objective, many writers get accused of selectively editing things: Philip Greenspun's account of the demise of Ars Digita springs to mind. Or Jerry Kaplan on Go (mobile startup). Or Joel Spolsky on the last decade of StackOverflow.