It is not a top down approach , its cross functional . Everyone has a say in Amazon. During meetings, everyone's idea is taken into account and as a team they discuss and moved forward.
The work culture in Amazon is one of the best when compared to all multi national companies across the Globe. They allow the employee to adapt methods which is mutually beneficial to the employer and the employee. Also the organization strictly follows the 14 leadership principles which eases the solution to any problem that occurs on a day to day basis.