Just remember in the end of the 80s and the begging of the 90s, Japan was on the verge to become the world most powerful economy and market crash after that... 25+ years later the market is still almost in half - so many retirement money lost and a great example why buy and hold for a long time is actually not a good retirement strategy...
It means that all those robo fintech companies and the Vanguards of the world are making a lot of money, but "buy and hope" is not a good retirement strategy for the little guy, especially if you are close to retirement and you have some money set aside and count on them to live off...
