Assuming your calculations are correct, this means an issuer can only emit 8 cards in average to the total population.
Cards have an expiration, people lose them, break them, they change and come back to banks. For the main issuers it’s not ridiculous to have to issue 20 or 30 cards per account to a user in their lifetime.
Then people have multiple accounts (e.g. my mortgage was on a separate join account).
There’s just enough normal circumstances to run out of numbers, not even considering freak cases.
Assuming your calculations are correct, this means an issuer can only emit 8 cards in average to the total population.
Cards have an expiration, people lose them, break them, they change and come back to banks. For the main issuers it’s not ridiculous to have to issue 20 or 30 cards per account to a user in their lifetime.
Then people have multiple accounts (e.g. my mortgage was on a separate join account).
There’s just enough normal circumstances to run out of numbers, not even considering freak cases.