Well, in essence that is true for us, too. You asked a ludicrous hypothetical question and I should have just given you a ludicrous hypothetical answer, instead of attempting to actually address it.
Neither have our prophets. I can think of only twice in the last hundred years or so.
Simple. As long as the prophet speaks the truth, the Holy Ghost will confirm it. The prophet has never given new revelation that the Holy Ghost has not confirmed in the minds and hearts of the members of the Church.
Paul said it best, when he spoke of the organization of Christ's Church here on Earth: "And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers; For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ: Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fulness of Christ: That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive..." (Ephesians 4:11-14)
Without Prophets and Apostles, the Church would be left without its foundation and would be like "children... carried about with every wind of doctrine."