Detailed version of SPX stages as per the Minksy model. The popularity of indices have come a long way over the last decades.
Back when Bogle first marketed and popularised the idea, it was deemed to be "Un-American". Randomly allocating value to things based on their placing in an index. That's basically communism. That's the kinda thing that was being said back in the day. But Bogle persisted and the indices uptrended and here we are.
We now live in an age where indices are essentially considered to be magic. Can't go wrong as long as you're in it for the long term. Millions of people either choose to or are obligated to auto-invest into these indices on a monthly basis. It's gotten to a stage where society is heavily influenced by what these indices do.
Have the indices gotten safer as time has went on? Probably not. The weighted indices have had the default effect of allocating the most capital to the biggest stocks and facilitated the concertation of capital into these stocks - a form of malinvestment. "Removing price discovery" - as many have lamented in the recent years.
If it happened to be the whole idea of passive investing fit inside of the Minsky model - we'd now be in the extremely advanced stages of it.
