Yes, if one were to stop using the subjunctive mood, the subjunctive mood should be dropped, because there is no point to having language that no one uses. The subjunctive mood is part of language, but language is elastic. Language is always changing. If a part of language is no longer used, it is okay to let it die out.
The question itself is in the subjunctive mood. Such moods are necessary to properly convey the intended meaning of the sentence. Since they are necessary, they will not stop being used in the first place. Further, we can see by the example of languages other than English using the subjunctive that it plays an important role in human dialogue.