Jane: Did Spot like the toy I bought him?

Martha: Yes, he has already ripped it to shreds.

Jane: Well, so much for that toy!

We say “so much for X” when X has been destroyed or ended. In this case “so much” doesn’t mean “a lot” but “that specific amount.” The thing we are talking about only lasted this long.




「So much for ~」は、その~が破壊された又は終わったときに使います。この場合の「so much」は「たくさん」ではなくて、「このくらい」です。話しているものは、もはやこれまでだった、これ限りだったという意味です。