It's not just retail profit.
It's shipping costs. Storage costs. Labour costs. Overhead costs. Taxation.
Many of which are not fixed per unit.
Plus.
Currency exchange.
The risk cost of currency exchange: the less stable the currency, the greater the insurance premium that gets factored into the cost.
Plus.
Market power.
Competition.
Regulation....
All of which may exist because frankly there are things you DO want more than cheap retail.
In other words, the whole of the economic machine.
"Profits" tend to evaporate when examined under the light.
Unless it's a bank.