Because it is one of the most sensible options to protect wealth. It’s challenging to beat the market. And sometimes, you can beat the market randomly or accidentally but still assume it was because of your chosen strategies. And no industry is impervious to “black swans”, no matter what the data looks like now. Technology, in particular, can be a complete game changer.
A diversified portfolio can actually reduce your total exposure while also reducing the time you need to research the market. You don’t need to know it all when you are diversified because you get a piece of many pies. Robo-advisors are a form of passive ETF investing without users having to do any work besides saving and investing.
And there is much evidence that passively diversified investments beat actively managed funds, especially when management fees are accounted for.