As I used to work in the Storage and Material Handling industry for nearly 20 years and my husband actually designed similar, if not bigger, warehouses for Ikea, Co-op and MOD the warehouse was actually fairly well designed.  Except for one thing they could have got a faster input if they had teams working just one floor rather than having to put trollies in the lift and staff walking up.  It is a well known ploy in the picking industry that managers work out what the average pick time is and then add 15% - it has been going on for years, it is nothing new.

If I had a choice of working at Amazon 4 days a week in the dry and the warmth with a trolley or a postman with a bag over my shoulder in the wet, snow or cold I know which I would choose.