Originally banks were paid to look after your spare cash. Keep it safe.
Then they made a margin by offering a small return on savings and charging a slightly higher percentage to those who wanted loans.
Banks needed customers to make savings so that they could then put that money to work as loans to turn a profit.
A lot of banks were state owned.
When banks were privatized, ownership passed to the new shareholders. These new owners now all expect a dividend from the bank. This dividend has to come from the difference between the interest paid out to the savers and received in from the borrowers (and now more and more frequently from fees).
So either the bank makes less money or the punters get less/pay more.....
The privatization of the banks was 'sold' as allowing more competition and therefore giving a better deal to the punters. But that doesn't work, does it?
The banks used to be dependent on their customers. Now they are subservient to their shareholders. This means they are far less customer focused.
Which is probably why they are such a massive pain in the arse to deal with.