maybe 3-5 years ago, and further back than that, upgrades often happened at the windows. Not so much anymore. UA would rather have cash, so waits until it is basically no longer possible to get $ for the seats before they do CPUs. They’d rather wait until every opportunity to get those last pennies is gone. In a world like today where $ and short-term ‘get $ now’ thinking pervails, especially among the investors the large corporates are pandering to these days.

Yesteryear, before pushing what used to be ‘TODs’, they would upgrade into seats they weren’t expecting to sell tickets for. Heck, pre CO merger, UA had a separate fare class NF, and as soon as seats became available in that class, those upgrades would instantly come through (meaning NF would essentially always be 0 if there were elites within their eligible windows), unlike today where upgrades, if available, are only ‘pulled’ through at the windows, but again, it’s rare these days.

Essentially, they are would rather have cash, and they are able to sell More F seats as opposed to giving them away. That’s why many people on this board say if F is important, buy it. Even as a silver I used to have upgrades on as many 40-50% of my flights. If I get 1-2 upgrades a year these days, that’s a lot.