Ok, that's good, but what's their profit? No one gives anything for free, that's a rule that I have learned a long time ago.
Do you have a bank or credit union account that pays you interest? Well, there ya go. Wall Street has been charging fees because they can because everyone has been. Now, that's blown out of the water. This, of course follows Fidelity's Zero funds (and the much less known SALT funds that have negative ERs....yes, they pay YOU to put your money in through them....although they say it's temporary).
Brokerages make plenty of money without a lot of their fees. I have nobody calling me up from Fidelity to try to move my low cost index investments to high priced, actively managed funds, even though they know who I am when I've walked into an office to get some help on a form. "Oh, you're the indexing guy". Yup, I'm the indexing guy with well over a million dollars of non managed, low or zero cost investments.
Jack Bogle: "You get what you don't pay for". I live that. My average ER over my entire portfolio (as of this morning) is 0.0196%. If I include my US Savings bonds, it's 0.0168%. And there is room to reduce those numbers.