The article comes to the exact opposite conclusion.
The article repeatedly cites problems associated with culture breakdown, and tenured employees are a key source of continuity for culture. The article goes to some lengths to underline that the culture is a positive and key differentiator for Amazon.
The more interesting point is that the cultural element looks like it is highly durable and effective, but has broken down as Bezos (the most tenured employee!) has pulled back. So it's not as durable as everyone thought.