Thanks for this insightful article. What we often forget is that book publishing really IS open to everyone, and every writer who wants to publish a book should do it. Amazon or Apple or Google books might be the only options available, and that’s okay. Just because Amazon didn’t turn out the success to be for some should not preclude this venue for others.
What about if you want to publish your collection of novellas in Spanish? Do it!
What about if you feel to publish your diaries from when you were roaming Paris or Florence or Kathmandu in your 20s? Do it. Why hold back?