Ma and Pa will not lose the money in their account, which is guaranteed by the federal government. Remember though, that the Savings and Loan crisis cost the taxpayers 160 billion dollars. This will be bigger.
When Franklin National Bank in New York failed, (about the biggest bank to fail since the depression) around 1973 or so, it didn’t cost the taxpayers or the FDIC or big depositors a dime. Franklin National Bank closed Friday (and in the day before ATMs and weekend banking) opened on Monday as European-American Bank.
A German banking consortium took over the assets and liabilities “as is”. I can see a number of smaller banks being rolled up by the larger banks and cash rich foreigners buying up the failing larger banks. Banks actually hold very few direct mortgages, though they are invested in the paper of mortgage holding conglomerates. The idea was to diversify risk. But risk diversified became risk ignored, denied and hence the current mess.