Agreed, it's well done, but here is one factor they mentioned, but did not explore: ...
And here's another one:
Total awards (millions) 11
Avg miles per reward 23,818
How do we arrive at that number, considering that DL's cheapest award (assuming you can find it on the "low" level) is 25,000 miles? Is this telling us that a significant portion of the 11 million redemptions is for giftcards and other junk?