That requires putting one’s faith in the vapor-currency that is crypto. Not saying that it won’t happen one day, but neither is it necessary to solve this problem.
A simple Paypal button, for example, does not require DRM spyware if done from a website on a FOSS stack. The Paypal tax is is mere pennies compared to Amazon. A bank transfer has no tax at all, tho it’s not great in privacy terms.
But where do I get the author’s Paypal ID or bank number from? I want you pay you directly, dammit, but you insist on allowing to Amazon tax the transaction and to force me to install spyware to read your damn book.
This is a cultural problem as well as a technical one, of course.
IMO we need to get to world where enough authors are happy to allow ordinary folks to “pirate” their work, and enough readers are happy to pay them even though they could get away with not doing so. In that world the technical solutions could so easy, so frictionless, in theory. But it takes a leap of imagination for everyone involved.