Board Thread:Naruto Discussions/@comment-33156423-20170923231447/@comment-1512913-20170926180521

Except there is no evidence they already had the basic components, that's just an unfounded assumption. The canon literally says that Kaguya was the first person on Earth with chakra, that Hagoromo and Hamura were first people born with chakra and that Hagoromo spread chakra to the world.