First of all, I am in Yerushalayim, so I’ll need to stop by shkiah.
Looking at the shulchan aruch/mishna berura, he also mentions the need to daven ma’ariv after. One could say that the mitzva of drinking only applies when one will daven a propper ma’ariv after (Ben Azzi type thinking of Yachor L’limudo).
i.e. the mitzva was never said in a situation which would result in no ma’ariv