They are highly profitable because they have an oligopoly over consumers. Consumers are forced to use them and other companies are forced to do business with them. For no other reason than a lack of alternatives. The reason that there are no alternatives is simply because they cannot compete financially... But if they could play on a fair/even playing field, the alternatives would almost certainly win.

Their high visibility is why they are able to soak up fiat from the economy. When the Fed did the trillion dollar stimulus packages, it went straight into these highly visible stocks.

These companies seem to be running a kind of money laundering operation at this stage. I suspect they found a way to keep borrowing large amounts of money from banks in perpetuity and then circulate that money among themselves to pay off each other's debts to inflate revenue numbers (maybe they use shell companies or corporate partners). It seems that there's something not right going on financially speaking. They're not playing on an even playing field as other companies. They shouldn't be profitable but they are; simply because they have an unfair advantage due to having special access to the centralized money printers.