I suspect that to his (and his publishers' minds) the collapse itself is the finale, and the trial is a marketing campaign. The more press the trial gets, the more people are going to get curious to learn about the background and judge for themselves, and just in time a book about the company/SBF by an author who is notable for his ability to explain and humanize complicated business concepts to a general audience is right there on the front shelf at Barnes and Noble.

If anything, when the trial is over they re-release with an epilogue evaluating the trial.