God forbid! Baha'u'llah has revealed a prayer for the future of Islam:But you are right that all religions are one. They were all equally abolished and expired.
… the breezes of Christ are still blowing; His light is still shining; His melody is still resounding; … and it is the same with those souls who are under His protection and are shining with His light.
(Some Answered Questions, 152)
Shoghi Effendi uses similar language in relation to the possibility of revival in Islam,The indwelling Spirit of God which, in the Apostolic Age of the Church, animated its members, the pristine purity of its teachings, the primitive brilliancy of its light, will, no doubt, be reborn and revived as the inevitable consequences of this redefinition of its fundamental verities, and the clarification of its original purpose. For the Faith of Baha’u'llah — if we would faithfully appraise it — can never, and in no aspect of its teachings, be at variance, much less conflict, with the purpose animating, or the authority invested in, the Faith of Jesus Christ.
(The World Order of Baha’u'llah, 185)
Shoghi Effendi is emphatic that the Bahais do not seek to abrogate ("abolish") other religions:in the field of religion … we have lately witnessed widespread and organized attempts to broaden and simplify the basis of man’s faith, to achieve unity in Christendom and restore the regenerating vigor of Islam
(Baha’i Administration, 145)
and he affirms that Baha'u'llah has recognised the high station of the leaders of previous religions:Let no one, however, mistake my purpose. The Revelation, of which Bahá'u'lláh is the source and center, abrogates none of the religions that have preceded it, nor does it attempt, in the slightest degree, to distort their features or to belittle their value. It disclaims any intention of dwarfing any of the Prophets of the past, or of whittling down the eternal verity of their teachings. It can, in no wise, conflict with the spirit that animates their claims, nor does it seek to undermine the basis of any man's allegiance to their cause. Its declared, its primary purpose is to enable every adherent of these Faiths to obtain a fuller understanding of the religion with which he stands identified, and to acquire a clearer apprehension of its purpose. It is neither eclectic in the presentation of its truths, nor arrogant in the affirmation of its claims. Its teachings revolve around the fundamental principle that religious truth is not absolute but relative, that Divine Revelation is progressive, not final. Unequivocally and without the least reservation it proclaims all established religions to be divine in origin, identical in their aims, complementary in their functions, continuous in their purpose, indispensable in their value to mankind...
(The World Order of Baha'u'llah, p. 57)
Because the religions are complementary and indispensable, according to Shoghi Effendi, the eventual extinction of a religion, which occurs after many thousands of years, is to be mourned, not celebrated.Nor should it be thought for a moment that the followers of Bahá'u'lláh either seek to degrade or even belittle the rank of the world's religious leaders, ... "Those divines," Bahá'u'lláh has affirmed, "...who are truly adorned with the ornament of knowledge and of a goodly character are, verily, as a head to the body of the world, and as eyes to the nations. The guidance of men hath, at all times, been and is dependent upon these blessed souls." And again: ... (... etc: it is a long compilation by Shoghi Effendi, in The Promised Day is Come, p. 110)
It would seem to me that much of the problem with discussion of religion falls within the multi-faceted use of terms and the limitations of language. In one and the same breath we can state that there is only one religion, composed of all the religions."This is the changeless Faith of God, eternal in the past, eternal in the future"
There is only one religion from God, each Manifestation just expands on what the last one said. There is never any new religion just the old ones renewed.