they already work almost for free, since all the money goes to the publisher and retailer.

out of $20 book, the authors earn about $1 - $1.5, for e-books its about $1.7 - $2

The value from book sales goes to retailer and publisher: two large corporations, and in case of amazon - a single big corporation

so please cry me a river about amazon's lost profits earned at the back of the book authors

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

This is a problem of publishers and retailers, and not a justification for distribution of mind theft.

yes, exactly, annas-archive is the modern robin-hood that frees up the knowledge.

it is not a theft, because people using annas-archive were not going to buy a book in the first place and publishers incomes didnt drop due to annas-archive

Then what's the economic interest for writing a book

Very little. Aside from high-profile/best-selling authors who do make a decent amount of money, the vast majority of writers do it because they love doing it, not because they expect to become rich.

Now you can publish independently through Kindle or through learnpub. Would that not cut out the intermediary fees?

not by much, kindle authors earn 70% royalty only if they price the book between $3-$10.

outside that range they get 35% royalty

so it is marginally better, but overall I cannot say that anyone got rich off of slaving away for Amazon Kindle, Inc