Great post, Will. There's been downward pressure on fees for several years now, and frankly I'm surprised it's taken this long to get close to zero. I think the future financial advisor/fee model will look something like this:

0% fee for anyone under 30 or with a portfolio under 100k
.25% fee for people aged 30-50 or with a portfolio between 100k and 500k
.5% fee for people aged 50+ or with a portfolio above 500k
1% fee for portfolios above 1 million

The added services that justify a higher fee (such as tax and estate planning) don't really come into play unless an investor is near retirement or has a reasonably high net-worth. The vast majority of Americans should have easy access to free or nearly free financial advice, with the option to pay more for specific add-on services.

The elephant in the room is what happens if 90% of U.S. investors all have capital committed to the same handful of index funds? Does that make the market, and therefore everyone's investment portfolios, safer or more volatile?