Humans, Gorillas, and Chimpanzees are all "cut from the same cloth" (share common ancestors) as well, but they've each evolved into discreet lines since due to adaptations for their relative environments.
Religion evolves in much the same manner - stories diverge with retelling, traditions are adopted from absorbed groups, and new shit is made up from time to time to keep it interesting, and over time they become incompatible.
That happened long ago for Judaism, Christianity, and Islam, and it's been happening within Christianity since the 16th century - in around 500 years, Protestants have created some 50,000 sects that largely believe the church they originated from, with its 1.5B adherents, are idol worshipping heretics.