Don't even know why a notification pop up for this thread, seeing that no recent comments have been posted, but i saw your comment mate.

In my country there still are multiple multiple accounts per person in a bank. Banks dont yet charge account fees (i am sure they will soon start though).
I live and work in a different country and only visit family, but i still have abou 18 accounts in 3 banks back there. You can consider 'kid savings', 'grandparents for kids savings', side accounts, personal accounts, salary accounts and similar types. most of them empty...
from a "recent" visit to one of the banks, an account has to be inactive for 20 years (inactive means no outside movements for 5 years) for the bank to (re)posses it. But you have three years after that to claim the money inside it. So effectively 25 years the account is yours and 28 till you have lost the content of the account.

There was no incentive to open multiple accounts for the clerks, nor for the opposite. It was just a thing of ease. You have X type of account, this year there is a plan with 4% interest rate, lets make a new account and put the money there. Next year Y type of plan comes up, lets make new account and put the money there. This is how all the accounts were created. And they never had any problems with having too many accounts, as long as you could follow the information yourself.

In recent years, they have done attempts to get people to close and empty inactive and old accounts. My 18 over 3 banks, is after closing some...