I haven’t seen Brokeback Mountain...in general, I don’t go in for tearjerky romances too heavily. However, I do live in the World and sally hither and yon on the Web, and therefore I am familiar with the oft-quoted, oft-parodied “quit you” line.
Perhaps through the many Brokeback parodies, perhaps through the quoting, this once-archaic usage of ‘to quit’ for ‘to leave or depart from’ is gaining currency. Witness its appearance in Rolling Stone (“When asked if confirmation of her cheating would have been enough to make him quit her, Lachey hesitates.”)
I find this fascinating. Our language churns constantly, creating and destroying words at an astonishing rate — these days, sped along by the Intarnebs. How often, though, is one work, one song or movie, responsible not for inventing a word or innovating a new use for it, but for reviving an old use? I cannot at present think of another example, and therefore leave it as an exercise for the reader.