Agreed completely. I don’t know how anyone can justify 10 times the fees using wealthfront for non trivial amounts of money.

I personally have many friends who are very happy with betterment and wealthfront which is good. When I ask them about their returns in the past couple years they say that the stocks have done amazingly.

When I tell them SPY would’ve given them higher returns and lower fees they’re skeptical, and lo and behold when I actually show them they’re shocked.

I feel these companies survive on sheer inertia

I don't know what are Wealthfront's fee, but not everyone wants to put all their eggs in SPY. Wealthfront (and other similar services) let you pick a risk score, and based on that invest in lots of different things. Most people have very diversified Wealthfront portfolios. They also claim to help with tax harvesting. Since SPY had an amazing run it performed better than your friends' accounts, but it doesn't mean it will keep outperforming in the future. It's a riskier investment.

Now, obviously you can also create a very diversified portfolio by yourself. That's totally fine if you know what you're doing and OK spending the time doing it.

A target date fund suffices for most people. And I would need evidence to believe that Wealthfront's fees are offset by the tax savings and increased complexity for 95% of people.

Not 95% of people but if you have capital gains from RSUs wealthfront losses can deduct from that. Not limited to $3k/year.

However generally they harvest only a few % of your portfolio

You assume that most people who want to invest even understand what SPY is, what a proper allocation looks like between stocks and bonds, what tax-loss harvesting or rebalancing is, etc. For those folks, robo-advisors provide a huge value-add in making it really simple to invest responsibly. If they were to do it on their own, they probably wouldn't know where to begin.

The kind of person who is using a robo adviser will probably know what SPY is, and even if they don’t that’s the purpose of my post.

I’ve yet to see evidence that any actively managed fund, including robo advisers, outperform SPY on a risk adjusted and fee adjusted basis.

One reason they've underperformed a bit is because they have a lower risk profile than SPY.

When the market crashes, I expect their autorebalancer to make a killing.

It's been hard to compete with "stick all your money into the biggest US companies" for the last few years, but those years weren't typical.

We could also tell you that VOO gives you the returns of SPY with 1/3 the fees, or that VT gives you much better diversification.

Schwab at least has terrible UI and doesn't always have accurate numbers. (For example, their GL/share for one of my mutual funds reports the wrong price/share, using the same value for every purchase, while viewing the history tab I can see the actual prices from reinvested dividends...)

Not saying they aren't saving you the fees, but not a lovely experience.