Bookworm says
If your airport wants to provide greater protection for commercial users of that airport than is provided for in class G airspace, there is a well defined procedure for an application for controlled airspace which means that due process ensures the cost-benefit for all airspace users is considered.
and is therefore presumably aware that in order for an application for Regulated Airspace (a more accurate term I think) there are a number of loops to jump through - one of the most significant is meeting the minimum number of passengers shifted. Close to my home, Exeter and Plymouth are both commercial airports handling significant numbers of passenger flights, with only an ATZ to protect them. It's not quite as simple as you make out?
...But that's getting away from SS's point