Honestly, I don't understand the current dynamics of the band. After listening to a considerable amount of leaks (demos and unreleased tracks) I came to the conclusion that the band has really good material that can be finished and even reworked, but at the same time I feel that there is something that is preventing them from releasing it. What exactly? Well, I don't have the answer.
I believe that "Alphabetica" is a conceptual title for a future project and not something definitive. It is worth remembering that in 2010 the band was going to release a new album but it was scrapped and now all that is left are a few leaked tracks, such as: "Spanish Rain" and a demo of "Love In A Lethal Dose". Of course there are many other tracks from this 2010 album. What I mean is that when it comes to Chris Martin himself (who is a perfectionist lol) openly talking about future projects, it is not possible to be 100% sure that it will actually happen.