These aren’t businesses. These are websites. Most people on HN can build a website. It takes some coding and some tech knowledge. Not everyone can build a business. That involves marketing, advertising, customer acquisition, cash flow management, legal, on and on.
While what the author did was neat and fun for him, let’s not pretend this is the path to a successful web business. I’d bet there’s few “micro-bets” that are generating any meaningful amount of money.