To me this is a sign that the end of traditional publishing is very near. They milk the last drops from a dying field ?
But if by "traditional publishing" you include electronic publishing, then I'd agree, something is probably going to change soon. It's clear that you can get much more education in today's world in ways other than books.
Truth be told, we go to early access largely because we think it helps us make sure the book is delivering the goods, collect feedback, and hopefully improve the book as a result. We try to make it very clear how much of the book has been written - indicating what chapters have been written, and make it very clear that the book is unfinished.