Masa: first let me say that I appreciate your translations very much. Doumo arigatou gozaimasu!
"has already gotten" is very American. I've learned British English, so for me "has already become" is more natural. But I guess it's just a matter of preference
I think (as I said on ayumi-sg) it would sound more natural if "Why sometimes..." were replaced with "Why is it that sometimes...". The "is it that" doesn't really have any meaning, it just ties it together.
Another way to write it would be "Why ... sometimes?", but I think that it changes the meaning a little.