republicans are worried that he won’t win either which is why they aren’t going for him
I think it's more just the residual power of the old media and legacy institutions focusing on and donating to their preferred candidates. Republicans are almost as susceptible to that as the rest. There's nothing more "unelectable" about him than anyone else.
I'm an atheist, a member of the group he "disrespected" in his I'm proud Mormon speech. If people like me don't care about his Mormonism, how difficult is it for Christian America to not care about his Mormonism.
He's talented and capable, connects well with people and has slightly right of center principled policies and can fight. He's very electable, he just needs exposure to demonstrate it.