Company culture always decays over time to reflect incentives. Not to denigrate Andy Jassy as a Harvard MBA turned Marketing Manager who moved up to become a CEO. But upper management always ends up with the kinds of people who tend to reach upper management in any company.
That said, Amazon’s culture is closer to the norm than most startups so in the short term things are unlikely to change much. At least until some new management fad becomes popular or they run into a significant issue.