It happens that Chris Green formulated :
I know you can, but would you expect to always go to the farm for your milk, for your fruit and your veg? Would you go to the refinery for your petrol and diesel? To the weaver for your clothes? To the printer for your books? To the manufacturer for you car. There have always been middlemen and always will be, because there is a very obvious need to separate production from distribution and retailing.