The thing is that the bible was actually "engineered" with its books carefully chosen in the Nicaea Council while many other gospels were left out. For example there is one of them that states that Jesus said God is within us. How much would the church hate it if people started looking for god and salvation inside of their own selves instead of inside their temples? Since the books were written by Jesus disciples and they were mere mortals like any of us with their qualities and flaws, could it maybe be someone's ego getting on the way saying that Jesus told 1 specific guy that he would be the responsible for founding this church? Historical and texts manipulation isn't something that started recently and these ancient texts have been through the hands of several people, translated and interpreted over a long period of time.