I can't begin to cover that for a variety of reasons, but among other things the very
optimistic - okay, naive - post-production schedule didn't allow for any major delay.
For example, a single visual element that required a change in artists necessitated starting from ground zero on a shot that we thought was fairly well along. That pushed back release of Act One some months - at which point, additions to the families of a couple of the producers required their curtailing the time they were investing in the project for a while. The whole plan - again, naive - was lined up like dominoes and when the first couple fell...well, you know dominoes.
No, that doesn't begin to explain the length of time this has taken. There's a lot more having to do with unanticipated needs for reshoots, and a really strong drive on the part of several of the principals to raise the bar on what they deliver with each new segment. And then a whole bunch of other stuff. But it's the best sort-of-little-bit-of-an-answer I can give you right now.