How will banks recoup their dented profit margins?

The banks always find various ways to recoup losses through their customers.  When credit card charges had to be reduced from as high as £39 to £12, some responded by tagging on an annual fee, some have already started fining customers who are in credit and other like RBS reduced the interest free period their customers have before payments are due.  And there have been many others setbacks; mortgage exit fees, miss-sold Payment Protection Insurance (PPI), various bank account charges, and now the US sub-prime mortgage crisis.  They have already started by increasing mortgage arrangement fees to as high as 4% of the loan.  The banks are very shrewd in finding various ways to pass the buck!