As somebody who has started businesses, the "investing your money in an equity exactly as you would treat investing in a business" strikes me as great advice if you have plenty of time, and bad advice if you don't. Investing in a business is very hard work.

I know people who do pick stocks exactly as you describe, and they do just fine. But they spend a lot of time and attention on it, and they have years of expertise. The question for me isn't, "Can I do the same," it's, "Can I do something better with my time?" For me, the answer is yes. Trading stocks is making money, but it isn't creating value. I'd rather focus on creating value.

In theory, I get your "What if one day nobody traded stocks? Index funds would be doomed!" point. But in practice I don't think we're near that point. There still seem to be plenty of business news, plenty of business reporting, plenty of people fussing about individual stocks. Indeed, it seems like way more than we need. I don't feel obliged to add to their number.