Want to know the easiest way to become a millionaire?

First, become a billionaire. Then, start an airline.

4% seems reasonable, it's pretty much standard across the board in Europe (median sits around 6% if I recall correctly), not many companies can pull 10% profit. For example in Spain, major conglomerates like INDITEX have a 11%, Iberdrola has a 10%. We also don't use the same metrics and parameters as the US for profit, so the values are skewed.

That said, certain sectors like software (as in custom enterprise grade software dev) pull revenues that are much much higher sitting around 35%, but it's not that common.