Remarkable guy. Was incredibly passionate about index fund investing and low-fee funds. Just in the fee reductions, as you said, he has been responsible for billions of dollars staying in people's pockets, not just in terms of Vanguard's assets under management, but in how he pushed other money managers to compete. He revolutionized that business.
He was a plain-spoken, smart, really nice guy. He could have been worth billions of dollars with the company he created. But he gave away so much money to charities and various organizations, and he died worth only about $80 million. I know that is going to sound like a lot, but to put it in perspective, the kids of Edward Johnson (founder of Fidelity) are each worth $10 billion +.
Bogle's name may not resonate with a lot of people, but he was a giant who has impacted millions of people, whether they know it or not. RIP.