Even though ORD is a UA major hub, don't expect any breaks.
I've family there, and often asked to come to something or other with relativly little time.

What ticks me off is I could book a tkt for tomorrow from SAN-MCO, or SAN-BOS, for less than a third the price of ORD. Oh well.

And then every airline wants to get the most for holiday season.

Lesson is, if the cpm is reasonable, take it.
Theres always SW, or others.