Share your insights or perspective on the financial matter presented in the input.

Is a “total stock market” index fund diverse enough alone?
I don't think you are missing much, if anything, Brendan. You get massive diversification and low fees with a fund like VTI. I'm not sure if it is good to have everything with only one broker though. I would add to the conversation that the goal shouldn't be to have a giant pile of money in x years..and then spend it down in retirement. A much better/safer goal is to have enough dividends being generated that you never have to touch your capital. Looks like you are starting young so congrats.