I think it makes an excellent case for common ancestry, but does it make a strong case for universal common descent, or in your words “common ancestry of all living things on earth”? Many creationists would agree with a significant amount of common ancestry, I think, but disagree that it is truly universal. So do scientists have a sense of how universal it is? In other words, has there been enough tests like what you and @John_Harshman have done across not only multiple sequences in the human genome compared to apes and monkeys, but across the entire “tree of life”?