Telecom rate tarrifs are usually convoluted and political. Some places have the opposite of what you outline, where international calls pay an extra kickback to the telecom/government. Other places, like the US, had things setup so that calling people inside your state was more expensive than calling another state or calling from an international location.

This also creates incentives for people to setup grey routes. It's common to buy local prepaid SIM cards then hook them up to a GSM bank and sell "international" connectivity to calling card companies. One guy had his setup inside a van, so he could drive around town and avoid being triangulated by the local telco. (The local equivalent of the FCC will raid and steal your equipment if they can find you.)