To answer the only question I can see in this... blurb, no Kubo has not lost his mind. It is true that Aizen keeps getting stronger but so is Ichigo. Therefore, when both the main protagonist and the main antagonist are mutually capable of gaining infinite power, it stands to reason that the author does have some plan by which to dispose of the antagonist. I'm sure there will be, but for now, please let Kubo-san do his job. I'm sure answers will be brought throughout the series.