That's not true either.

Both land and other stores of value (eg gold & silver) were frequently traded between medieval landowners.

Even looking at Europe alone, the Kinghts Templers acted as bankers as early as 1000AD, which allowed the rich to transfer money over distance. By the 1300's the Medici's had created an institution that would be recognizable as a modern bank.

Interestingly, the Medicis also created the prototype for modern, "democratic" government. I found that incredibly fascinating and confusing.