The "market" has decided that Amazon deserves a near-total monopoly on the e-book reader market, which allows them to unfairly pressure publishers who have no realistic alternative if they actually want online sales. (Publishers are not a fan of Kindle unlimited.) Just recently Amazon released a book ahead of embargo and they will face zero repercussion for doing so.

A market that had more than one way to "publish" books online would be a different ballgame than the one we're playing now