Antonyms for the phrase "coming down the pike" could include "fading away," "disappearing," "dwindling," or "losing steam." These words suggest a decline in prominence or influence rather than an increase. Alternatively, a phrase like "going up the ladder" conveys an advancing or improving situation as opposed to a change that may not be positive. Additionally, antonyms could include phrases such as "going out of style," "fading into the background," or "becoming irrelevant or obsolete." These phrases suggest that the subject is losing its significance or importance rather than gaining momentum or attention.