Gas price at the wellhead only has a small effect on gas price...

Gas price at the wellhead only has a small effect on gas price for domestic consumers, anyway. A doubling of the gas price only has something like a 10% increase in the cost of gas for consumers, because the bulk of the costs are in transmission and on-selling to the distribution companies.

In NSW, depending on location and provider a customer using 5000 MJ per year will pay about $500 - that's $100/GJ! So it doesn't really matter whether AGL pays $4 or $8 wellhead price for the gas. Or even $12. You'd be paying $104/GJ instead of $100 for doubling the gas price from 4 to 8 bucks.

That said, NSW's delay in expanding CSG is ridiculous. They have been producing CSG since the mid 90s, even before Qld started. Successive spineless governments are just caving in to a Green-inspired fear campaign. NSW CSG is actually perfect for domestic supply (rather than LNG) and has minimal impact because the seams tend to be deep and have high gas contents, so they don't produce anywhere near as much water as Qld CSG. A limited CSG program to ensure domestic supply would be perfect.