You are assuming deposits and loans both are done in terms of bitcoins.
In theory, we can design a banking system that accepts deposits in bitcoins and gives out loans in the fiat currency.
In theory, we can design a banking system that accepts deposits in bitcoins and gives out loans in the fiat currency.
Also, such a system mutes a key feature of current "money multiplier" based systems, which is recursion. Under the current system, when you deposit $100 in a bank, that bank can then lend $10 to nine other people. Who can then each take that $10 and deposit it nine other banks, which can each lend $1 to nine other people...
Without this effect, the money multiplier would probably need to be tweaked pretty drastically.