I guess there was a time clause in the contract as well. But you have a point there. Since they had no expenses other than the high advance and mixing, and the salary of the ones involved, they could stretch the time. It is not like we had a rival official release. I guess many people like me and you that couldn't afford it or thought of them unnecessary back then, would reconsider and buy them now, as downloads or sticks. (I would go for the sticks.Anyone out there selling?)
But answering to some questions about the download of the concert with the Box edition, being incomplete, maybe that is why they couldn't include the whole show. In order to keep the customers of the sold Simfys at ease, that they still have something unique. And maybe there was a clause in the contract as well.