Amazon CEO Jeff Bezos' annual shareholder letter, once an insightful must-read, has turned cautious and promotional as the company faces more scrutiny (AMZN)

· Amazon CEO Jeff Bezos published his annual shareholder letter on Thursday.
· Bezos's letter has become a must-read among business leaders for its ingenuity and thought-provoking advice.
· This year's letter, however, mostly focused on Amazon's work in helping its employees and other businesses amid COVID-19 — a departure...