The hegemon concept is also out of date. World trade is not dominated by countries but by multinationals. For instance, there are no real "US" car companies. There are a handful of huge conglomerates who can choose to operate wherever best suits their needs. These respond to edicts from individual countries but operate at a level above nation states.
This is why international cooperation on things like taxation or environmental protection is so important. And it is why petty bickering by individual nations will be so damaging.