famousmortimer suggested such a thing. I have my own source on that subject as well, but I cannot reveal who that is. But trust me when I say it's no random individual.
Again, I don't want to try to be seen as an insider. I absolutely am not. I simply have heard a few things about one or two subjects recently, and it's one of the first times I've ever heard stuff from credible places on my own.
Well, they actually have more than that. They don't necessarily have to have the patch ready on DAY ONE. They may continue to work after and maybe release a patch before Christmas. I think gamers ultimately would be happy if they could get some level of improvement via a patch than no improvement at all, right?
I think it was probably that they got it up to the resolution but it wasn't at a stable framerate. They probably thought with the added months, they'd be able to get it at a consistent framerate. Since 60fps was pivotal to the series, they probably realized they wouldn't be able to reach the goal if they wanted to hi the launch deadline (especially since Microsoft is a partner with them, and they don't have the luxury of a delay).
This being caused by the added complexity of the ESRam memory architecture and the tools being considerably behind PS4's. Add the fact that the XBO is significantly less powerful to begin with, and it was the perfect storm.