Yglesias is a political pundit, not so much an economic expert. He doesn't understand reinvesting profits to grow a business.
- He wrote Slate's economics column, "MoneyBox," for a number of years.
- He wrote a book about the economics of the housing market.
- He co-founded Vox.com, which -- presumably -- reinvests its profits to grow the business.
I'll add that his writing was good enough to trigger a response from Bezos in a letter to shareholders.