Therefore, they are intentionally holding back upgrades rather than just giving it to us and holding only an handful of F seats? I seriously doubt PIT-ORD has a lot of walk up full fares on a Saturday. Same goes for ORD-SLC that just passed the 1K window. Putting me at the whim of a mileage upgrader, someone who secured a 'sales' RPU/GPU, a customer who is on a flight where F is full and decides to switch over to my flight, elite customers who got rebooked in full Y in IRROPs trumping me in the queue despite buying a lower fare, etc.

sCO was like that [one time on 545am LGA-IAH the flight only had 2 of 20 F seats booked and not one upgrade was processed until 24 hours out], I was hoping they would do more of a hybrid approach in the merger by being more generous with releasing upgrade space at the window rather than holding back more than half of the F seats until they give up on trying to sell those seats.