The impact of Jack Bogle on the world of investment is, by any estimation, huge. Whichever side of the active versus passive debate you sit, it is undoubtedly true that the fact there is any debate at all owes something to Bogle.
As Steffen Scheuble, chief executive at index provider Solactive, says, Bogel was the "father of passive."
"The whole industry circulating around passive investment is beholden to his efforts," he says. "His approach to socializing investments was very disruptive thinking within the industry."
It was back in 1976 that Bogle launched his first passive investment, the First Index Investment Trust, amongst much US investment industry suspicion and even derision. It had a mere $11m in assets under management.
Yet today, the company that was formed off the back of that first trust, Vanguard, is the second biggest investment firm in the world, worth over $5tn and a company which truly deserves the appellation of behemoth.
Understandably, the current chief executive at Vanguard Tim Buckley was keen to praise Bogle's contribution not just to the company but to the wider investment world.
"Jack Bogle made an impact on not only the entire investment industry, but more importantly, on the lives of countless individuals saving for their futures or their children's futures," he said. "He was a tremendously intelligent, driven, and talented visionary whose ideas completely changed the way we invest. We are honoured to continue his legacy of giving every investor 'a fair shake'."
James McManus, investment manager and head of ETF research at Nutmeg, pointed out that Bogle was above all a maverick and a contrarian because he established an index fund when few when "few were questioning the wisdom of a stock-picking approach."
"He was also a maverick in the way that he structured Vanguard - as a mutual that was owned by its investors, rather than by him," he added.
Leaving a mark
His legacy for the investment industry as a whole will be that he forced the issue of costs and what that meant for any investment, high up the agenda. As McManus says, he was a forceful advocate of passive investment throughout his latter life and was "relentless" in his focus on the costs of investment and the needs of individual investors.
Not for nothing did Buckley point out that generations of investors and their beneficiaries can be thankful for how he changed the investment landscape.
"For many he was, and still is, the face of passive investing and without his personality the industry is unlikely to have grown to its current size."
Whether the industry would have grown as it has without his effectively leading the charge is perhaps a moot point. We will never know whether the passive industry would have developed the same way without such a forceful character. But the whole passive industry still owes him a debt of gratitude.
"A fact, which we can be certain of, is that Jack was a visionary and a pioneer," says Scheuble. "He fought against all critics and stood for what he has believed in. To put it on another perspective: many people have great ideas. Not so many own the dedication to fight for it. So, in the end, the whole concept might actually have needed someone like Bogle."
None could have foreseen exactly how the passive industry has grown - and certainly the notion of the world of ETFs - would have seemed very alien back in the 1970s. Indeed, in his latter years Bogle often took to criticizing aspects of the developing ETF picture, in particular smart beta.
His opinion in this regard is what might be termed ambivalent - many commentators have suggested that the relationship between Bogle himself and ETFs is akin to Dr Frankenstein and his monster. And certainly, the fact that Vanguard itself has taken to ETFs itself certainly didn't represent a commendation from Bogle himself.
But without his impetus, it is doubtful the debates surrounding ETFs would be happening at all." I assume that by the time he developed the concept, he could not foresee the number of assets under management, which are in passive investments today," said Scheuble who explicitly acknowledges Bogle as Solactive's "spiritual guide."
"His ideas have helped millions to accumulate wealth and to retire prosperously," he concludes. "I think he was really proud of the outcome of what he has initiated. It is, indeed, very impressive."
Perhaps the last word should go to perhaps that most efficient of active investors, Warren Buffett, who consistently praised Bogle over the years for what he did to democratise investing. "Jack did more for American investors as a whole than any individual I've known," he said after the news of Bogle's passing. "A lot of Wall Street is devoted to charging a lot for nothing. He charged nothing to accomplish a huge amount."
That is, indeed, a telling legacy.