I thought banks in its basic form is that they hold people's money. Why do the largest banks have such power/influence over politics and other aspects of society?
moneypowerinfluence The equation of capitalism.
Governments made a deal with them to lend almost unlimited amount of money to the governments -- added to public debt ultimately repaid by their citizens -- when those citizens refused to allow more taxes taking that money directly out of their pockets. In exchange the banks were permitted to create risky investments with potentially large returns and the government would charge the defaults from those risky investments again to citizens' public debt. The citizens are nowhere near innocent in the process, as stinking piles of propagandist crap have suckered you into believing. The governments need the ever-increasing amounts of money to create more extravagant programs thumb-sucking little children in adult bodies citizens demand. Those demand governments pretend to be their mommies and daddies and care for and protect them all ways and always. Governments can never protect citizens -- on the contrary they demand citizens come and die protecting them from enemies they make -- and most of the programs they create are far more expensive than if the citizens did it themselves. But citizens want to sit sucking their thumbs and cry for mommy or daddy government to fix it when the overpopulating hordes still spewing babies around the world crash economies by undercutting wages with their swarms of excess labor.