My assumptions originally led me to think that there was a God who sacrificed his Son to cleanse some kind of metaphysical force that He was incapable of cleansing on His own (because of some eternal laws that God is powerless against). That God was incapable of preserving the correct way to believe and access the rituals necessary to access the cosmic powers to cleanse the metaphysical force from our souls, so He had to "restore" it. The need for these rituals and beliefs is because, for some reason, God's home is incapable of having people around who are tainted by that force, and thus He has to punish them for eternity if they fail to access the cosmic powers through the proscribed beliefs and rituals. They also led me to believe in things like protective underclothing, mystical powers I could call upon as a man, because other men imbued with those powers by putting their hands on my head and did the requisite incantation. And so on.
I don't think it's a lost cause at all. I think there's a lot of positive things that people can gain from religious belief and practice. We are a very social species, and our brains like to categorize things. Religion often provides a framework to satisfy those needs incredibly well. There are a lot of moral, ethical, and spiritual (for lack of a better term) teachings that can be found within religions which can assist one in better understanding themselves and being more beneficial to their fellow humans in maximizing joy and fulfillment. Next to my bed right now is a copy of the Pirkei Avot, the teachings of Buddha, select speeches of Krishnamurti, and Ferguson's "Backgrounds of Christianity" (fantastic summaries of various philosophical beliefs around the 1st century). There's also a copy of Kim Foster's "Meth Lunches" -- kind of a religious experience in its own right. I've read many of the Sagas that are the foundation of much of Norse Paganism. I've made it through the entirety of Jordon's "Encyclopedia of the Gods" (birthday present from a dear friend). My father gave me a copy of Smith's "The World's Religions: Our Great Wisdom Traditions" in my early 20s, when I began questioning Mormonism. I've got English translations of the Tanakh, the Ethiopic Book of Enoch, and a few of Elaine Pagels' translations of gnostic texts. I've read Neihardt's "Black Elk Speaks," and Fenton's "Old Canaan in a New World."
If Mormonism makes someone a better person than they'd be without it, that is anything but a "lost cause." As an example, Dr. Peterson regularly notes that he can't imagine there being any morals without religious belief. If someone can't control themselves from murdering and raping with impunity, without belief that a deity said "thou shalt not," then I am all for them clinging to that belief for the sake of themselves and society. For me though, the more I've delved into other wisdom and faith traditions, the more I've found the waters of Mormonism to be incredibly shallow and unfulfilling to me.