Those trades are free because they’re executed with PFOF, customers get bad fills. Robinhood specifically has been know for egregious hidden costs in their bid/ask spreads. Institutional money and more serious, professional investors (with MUCH more capital than the average Robinhood customer) will continue to stay at more advanced platforms like IBKR and its larger comps, where they can route their own orders wherever. Paying a good honest commission is better than getting ripped off, and much less expensive in many cases considering IBKR’s volume discounts on commissionable products.