so much for sb/sth
so much for (someone or something)
Someone or something is no longer relevant, feasible, or worth consideration. A: "The mechanic said the entire engine needs to be replaced." B: "Well, so much for our road trip." The new CEO lasted less than a week before he was fired for improper conduct. So much for him.
so much for someone or something
that is the last of someone or something; there is no need to consider someone or something anymore. It just started raining. So much for our picnic this afternoon. So much for John. He just called in sick and can't come to work today.
so much for
We have sufficiently treated or are finished with something, as in So much for this year's sales figures; now let's estimate next year's. [Late 1500s]
ˌso much for ˈsb/ˈsth
1 used to show that you have finished talking about something: So much for the situation in the Far East. Now let’s turn our attention to South America.
2 used to suggest that something has not been useful or successful: She gave the job to the other manager. So much for all her promises to me.