This article has some elements of truth, but skips over some important stuff. In particular, the odds of making a living writing books when on salary, writing the books for a big company or celebrities etc, are vastly higher than just writing your own books. You don't have to beat insane odds if someone hires you for 70k/year to write books...you simply make that 70k/year. It's the same as e.g. people working in the video game industry. The odds of earning a middle class income as an Indie Game developer are super bad, but there are many thousands of people working salaried jobs in the mainstream AAA game industry who are definitely 'making a living'.
Also, this is nothing new. There is a reason 'starving artist' is a common term. For centuries, a lot of the most well known people in all creative fields were people who already had money when they started e.g. nobility, and some of those people were able to become famous, largely because they didn't have financial pressures that the vast majority of people had.