Let's be clear. DL has been more generous in rewarding miles vs the other carriers because Delta leads the charge in being a bank and not an airline. They have monetized Skypesos "the best" of all the carriers mostly via their partnership with Amex (the best airline/card tie up in the world I think).

The old guard is gone. The new guard is here. There's no such thing as cheap Skypesos tickets any longer unless it's a sub-500 mile route that nobody flies and Delta wants to dump tickets.

-RM