Actually not true - it’s mostly grocery store employees. But that’s my point entirely - not that Amazon would employ 2mm software engineers but that Amazon created enough value that it could scale to millions of employees each of whom are marginally contributing. A person stocking shelves or packaging boxes is a person with a job that creates value. The software engineers being deployed smartly created enough value in a virtuous cycle to allow Amazon to productively employ millions of people.

(And yes my 2mm is net of non full time employees while the I9 population is 1.5mm)

If as a book seller they had built empires they would be struggling against Barnes and noble still.