But they won't. There is nowhere near the support in the red states necessary for that to happen.
Think of all the businesses - and people - that have their money in banks that would essentially vanish when. The feds zap it all. Most people simply wouldn't want the headaches that would come with it until things got much worse than they are.
Well, we are talking theoretically, here.
As for money in banks that aren't local, I, personally am not so inclined.
Too damned much of my life is subject to the whims of people 2000 miles away, now, so I avoid the big banks for that reason, as much as possible. I don't bank online, nor with my phone, and resist doing otherwise.
As long as we are comparing to 1776, though, how heavily were the colonists vested in banks offshore? There was a dreadful shortage of Specie, (for instance, in MD and elsewhere tobacco was an accepted form of payment for taxes), coinage was fairly rare, and the various colonies either used British coin, Made their own coins, or even printed their own paper money.
In this day and age, investing in physical silver or gold or other commodities of value (semi-precious metal, for instance) remain easy options to preserve wealth, if not increase it.
"Junk silver" (circulated 90% silver coins) are already monetized, and could be substituted as a medium of exchange for small purchases at melt value or slightly adjusted. Melt value of a 90% silver US dime is $1.65, for instance, a quarter $4.13, a Half dollar at $8.23, a Silver Dollar, $17.68, and a full ounce of silver (.999) at $22.86. That could come back in style if enough people bought some to put away.
This is hypothetical, but don't think those in 1776 hadn't planned for the future, and taken steps to ensure their as best as possible. There are other possible items of exchange, but that is one whose purity and weight is pretty well already established. Especially with banking getting wrapped up in ESG and the possibility of social scores, "cashless society", etc. it might be prudent to have something to work with should you pop up as one of those flyover country hooligans that should be de-funded.