> Why doesn’t everyone just do that then?

I dunno.

We tell them to all the time but people think they’re smart and can outperform the market or they want to bet it all on large cap growth or are insistent that small cap value will our perform. Or they want to buy the cool new stock that totally won’t be a dud.

> Is that the only reason to add other allocations?

Bonds reduce volatility without significantly impacting returns. I have a link from /r/investing I can share when I get to a computer.

Everything else is already present in a total world index

“VT and chill” is a pretty common saying on /r/bogleheads