Schwab’s low expense ratios on some of their equity index funds are loss-leaders for their other products. For their money market funds, for example. Schwab is a for-profit operation.
Vanguard is an investor-owned coop with a laser like focus on lowering costs. Their customer service is also excellent in my experience. I have the sense that their founder (Bogle) and executives are multi-millionaires but not billionaires like Mr. Schwab and the family that owns Fidelity. Hey, no worries. I’m just saying you get better service, lower costs, and less jerking around at Vanguard.
Vanguard doesn’t have a branch network though, so for certain things Schwab can be convenient. I’ll also note that Schwab was a real low cost innovator during the 1970s. I’m not dissing Schwab. They provide a superior service package than most (all?) major banks in my view.