Re: Revenue and profit
That says everything you want to know about Amazon. Their employees pay their taxes for them.
So called employer taxes are, in reality, a part of the employee's income for the work they carry out, it is to provide pensions, healthcare and social NB welfare, it's effectively a tax on the worker.
As you say, a 3% gross profit is either the result of poor management or very good, tricky accounting.
The contributions to tax revenue made by employees via such things as VAT is nothing to do with Amazon's generosity to the nation or anyone else, arguably, if Amazon didn't exist those people would be working for somebody else and paying VAT according to their individual shopping habits.