When I worked at Telecom and people in Orewa and Pukekohe were complaining about making to calls to call Auckland, I vaguely recall their then-response to be something like "the Auckland free-calling area covers over 60kms), implying it was already big enough.

I suppose it's like the fibre rollout - all the people on here saying "it's just 500m from my front gate! Why couldn't it be extended?"...but there has to be a cutoff somewhere, probably the same for toll-free areas.

Telecom also used to sell a plan called "City Caller" (again from memory) - a monthly fee gave you free calls to your neighbouring toll area. Dunno if Spark still do it though.