There's a couple issues with withdrawing that much cash. First, it would wreck their balance sheet, especially at a credit union or something. Second, banks don't keep that kind of cash around, especially since the advent of fractional reserve banking. That means they can issue loans of up to 10 times the amount of cash on their balance sheet. So basically most money is in the ether as they say. That's why Bitcoin and crypto in general is so important to go mainstream...you won't need to tell anybody home much money you have or worry about authorities because you want to withdrawal a million dollars in fiat, because you won't need to.