Well, a few reasons, really. With the prequels there was a substantial ‘textual history’ which I wished to acknowledge and I’d gotten used to seeing the prequels with alternate titles and alternate end credits and things like that.

While working on TFA, I assumed it would be a one-off and I wouldn’t be doing anything for 8 or 9. So I left the end credits alone, and did not want to alter them that way. Plus, the changes made to TFA were trying to be elegantly invisible, moreso than with the prequels.

Now, it would seem reasonable to alter them. But, it would take some work and it doesn’t really seem necessary. For the prequels I typed and arranged all the pre-scrolling credits manually.