How much do you think it costs to make a pair of Nike shoes in Asia?

"Everyone needs a fixed percentage to make money"

I get they WANT to, and it's what a shoe retail strives for, but this isn't accurate.

Cars for example aren't 100% marked up. That would be insanity.

Shoe dealerships don't sell used shoes and have service/parts departments where they make most of their money

Because cars are a high $ item vs. shoes. A business's overheads don't scale linearly with item price, so it's possible for a car mfg to achieve a similar net profit margin to a shoe mfg but with substantially lower gross profit margins.