The offer of a bigger and better opportunity down the road, usually made by a producer, a director or lead actor in order to get subordinates to work harder or for less money or for no money, but the opportunity never arises.
From the web series TOKENS, Jessica AD says it to Producer in Episode 6 "Whitewashing" sc. 12. It's scripted as, "Thanks for the LA promise." Winnifred Jong, the series creator and director, got the actor, Jessica Greco, to adlib, "Thanks for the LA-fucking-promise."
by Roundstone April 8, 2020