A discussion of John Bogle’s legacy argues that Vanguard’s mutually owned structure, rather than the index fund itself, was the more important breakthrough. The account says Bogle identified the firm’s structure as the key decision that shaped everything that followed. The claim frames Vanguard’s ownership model as the inception point for Bogle’s broader impact, with index investing and the wider “Bogle Effect” presented as outcomes of that structural choice and Bogle’s later advocacy.