I don’t fly so frequently (was an average of once a year pre-COVID, this is now my first trip in four years), and when I do it’s often not Delta, but had ~55K miles from a bunch of family trips a decade+ ago, thanks to the no-expiration policy. It’s possible that I could have gotten a ticket for a while, but it seems that ship has sailed plane has flown, so I was surprised to see that at the 1¢-per-mile rate that many redemptions run these days I could upgrade to D1 (well, waitlist in this case) for the equivalent of $450. There was a bunch of “wait, what am I missing, this seems too good to be true” in there.