For years, Jack Bogle (the founder of Vanguard) has touted the benefit of passive investing, which is primarily driven by the relatively low fees they charge. Moreover, Bogle has highlighted the inability of active investors to outperform the market. Recent large investor flows into Vanguard products suggests that investors are increasingly agreeing with Bogle. See article here, WSJ.
Dolvin, Steven D., "Vanguard vs. the Industry" (2014). All Chapters. 108.