LAXRuss

While I don't know for sure, my guess is that maybe you were on a flight that was heavy with DL Plat Medallions and you stayed at the bottom of the waiting list because you were on such a low fare. DL's web site lists fare category as one of the factors they use in prioritizing upgrade priority.

So far this year I have been 4 for 4 on upgrades LAX-JFK. In each case, I was never upgraded in advance, only at the gate. I was always at the top of the upgrade priority list and in two of the cases seemed to snatch the last business class seat on this popular flight. My guess is that my 100% upgrade rate is because I was flying on a "B" class economy fare in each case. If I were flying on a U/T fare, I fear I might not have made a single upgrade on that route.