If the global pie stayed the same size, there was no margin for credit. Credit is the difference between today’s pie and tomorrow’s pie. If the pie stays the same, why extend credit? It would be an unacceptable risk unless you believed that the baker or king asking for your money might be able to steal a slice from a competitor. So it was hard to get a loan in the premodern world, and when you got one it was usually small, short-term, and subject to high interest rates.