The process of bringing diversified, affordable investment products to the masses started with investment trusts, which first appeared in the UK in the 1860s and afforded “the investor of moderate means the same advantages as large capitalists”.
Open-ended mutual funds followed in the 1920s, and were boosted in the 1990s byfund supermarkets which made them more popular by removing the initial charges for investing.
By contrast, passive investing is a fairly recent arrival. It did not start until the 1970s, when academic research started to highlight the fact that most active fund managers do not achieve better returns after costs than the broader market.