Audiobook is chapter-workflow. If export via project-page is the plan, every chapter has to saved as an extra song.
Better would be:
a) an option to have the link between a song and the master-project connected to a distinct version of a song - so audiobook-work different chapters could be saved as different versions of the same song and put in the project-page - avoiding saving every chapter as a different song.
b) even better would be a new audiobook-function "chapters" (that could bei placed on different tracks) with a vertical chapter-list to help fast switching between chapters - and having these linked to the project-page.