In consideration of what you've stated about her track record:
Imagine if RBG had less hubris, and stepped down in time for Obama to nominate a replacement ?
Fun Fact: She loathed Roe vs. Wade, thought it was poor law, and unconstitutional.
She knew that the only thing capable of passing Constitutional Scrutiny, would need to originate in the Legislative Branch; and has precedent in English Common Law through the UK Abortion Act of 1967 written as a Bill by David Steele.