Governments. You forgot governments. They take the bulk of the money, especially in Europe.
~25% VAT and then the publishers and retailers take their cut. The government takes another 40% in income and payroll taxes from that. The leftovers are what the author gets.
Buying from yourself is probably the biggest markup you can get.
yes, if you add VAT and remove taxes from authors' incomes, it becomes even more laughable.
its really might be better to publish for free and create a buy me a coffee