The publishers don't have to print, bind, or ship a book, and yet the price is the same as a hardcover, maybe a dollar less. B&N could have given a shot at opening up that market. But Apple, amd Amazon, and B&N probably colluded to keep prices high.
You’re right about the big 5 publishers colluding to keep e-book prices high, and Apple was caught up in that I believe, as there was a lawsuit a few years ago about that. But Amazon encourages low prices on e-books.
In fact, they only give their best royalties to e-books that are priced between 2.99 and 9.99. Independent writers, like myself, therefore sell our e-books far lower than the big publishers do.
Barnes and Noble problem was simply it cost a lot of money to keep retail brick and mortar stores open and if they don’t have the book you want, it can take weeks to get in. If you go to Amazon, though, they only have to pay for warehouse space so their prices are about a third less on paperbacks alone. And they can get you any physical book in two days for free if you are a Prime customer.
The small bookstores, like B. Dalton and Waldenbooks, always made more sense, and had better sales per square foot, than the big box entertainment destination concept.
Apple and the big publishers colluded. They had a press release about it, and then got fined.
So the publishers are telling Amazon that if you have an Ebook, the price must be just a bit lower than the dead tree version (at best). The publishing houses don’t want to go all ereader.
So right now, Amazon is the last one standing.