Long distance calls were expensive because they were trying to pay off billions of dollars of basic infrastructure - the phone network that we're only now replacing nearly half a century later. Those fancy exchanges that the phreakers were exploiting? Those had to be invented, prototyped, tested, mass produced, installed, maintained... and that's not even considering tens of thousands of kilometers of telephone wires and poles, negotiating land rights, etc.

We only think of long distance communication as being next-to-free today because our information tech is already bootstrapped, computers are a billion times more powerful, and the market across which those costs are amortized are at least a million times bigger.