Are Wealthy HNWI Or UHNWI And Highly Educated People More Likely To Use Robinhood Compared To Other Investing Platforms?

I am just curious as I (25M) currently use Fidelity as my stock brokerage and Coinbase/Kraken as my crypto exchange. For me, I just don't like Robinhood and knew about the Gamestop/AMC fiasco and their PFOF system. RH's customer service also leaves a lot to be desired. My cousin (31M) told me he is a genius investor and financial advisor but I have seen his account dip from 250,000 USD in 2017 to 50,000 USD in 2026 due to contrarian trading. My cousin (who has an SAT of 1350 on a 2400 scale, not a 1600 scale) put tens of thousands of USD in personal loans into Robinhood, only uses Robinhood, and will not switch to another platform. He owes over half a million in student and personal loans after having dropped out of pharmacy school 2 weeks before finishing his final course in Summer of 2019 (6 years in, having finished x out of x+1 courses, aka 1 course remaining). My cousin is now a W2 long haul truck driver making 90k a year in a 70 hour workweek and has been on the road for 6 years, staying in the same company. He stated that he will never leave trucking or pay his student loans and only pay off the minimum in his 350k student loans, and will only quit trucking and enter real estate once he becomes a multi-millionaire. My cousin stated that the reason why some wealthy and affluent individuals use Schwab, Fidelity, Morgan Stanley/E-Trade, Goldman Sachs, Vanguard, and IBKR is because they are forced to by their companies because their 401k is attached to it. He stated that they are willing to switch to Robinhood, but are stuck in these other platforms. He stated that the taxes on Robinhood are far simpler in format than the others, and he could use Robinhood on his phone whilst hauling a truck on the road. My cousin argued that it was the trader's fault for the Gamestop and AMC fiasco and that they should have not invested in it and looked at the company fundamentals. My cousin also argued that if an asset went up even 1 percent, it is too late as the ship sailed and you should only buy the dip.