There are other factors at play as well. Americans think nothing of lifting boxes and consider it manly! In Europe due to culture and strict Health and Safety Laws everything is lifted by mechanized equipment.Europe's warehouses are far more "cubed" than the US, needing constant use of higher lift narrow aisle fork trucks in the aisles. This mean you have separate equipment to load/unload. Americans use the same truck for both functions, and therefore have to have 14' aisles, which is ok because rental rates are much cheaper than Europe. Imagine you were building a warehouse near Manhattan, and then think of the things you would do, to get the most out of that space.
Material handling in Europe is treated with respect as a saving rather than a cost. Here equipment purchase is often at the company President's whim.