YOU SAID:

if this becomes that in the future then why is it the past?

INTO JAPANESE

これが将来的にそれになるとしたら、なぜ過去なのでしょうか？

BACK INTO ENGLISH

If this is going to happen in the future, why is it in the past?

INTO JAPANESE

これが将来起こるとしたら、なぜ過去にあるのでしょうか？

BACK INTO ENGLISH

If this happens in the future, why is it in the past?

INTO JAPANESE

今後こうなるのであれば、なぜ過去にあるのか。

BACK INTO ENGLISH

If this happens in the future, why is it in the past?