You get what you pay for.
As you would be aware navaids/facilities are most definitely user pay.
In a previous life I was involved in this area. This was how the system worked and I don't think it has changed.
If say a CAT III installation was desired at an airport the Board of Airline Representatives (which usually includes all the airlines operating through that airport) approaches Airservices with a proposal. Airservices then determines what the costs are for installation, flight testing, ongoing maintenance and any other other extras.
Airservices then inform the Board of Airline Representatives what the costs will be over the life cycle of the installation and how much the navaid charges will increase. The Board then refers the matter to the airlines to determine if they still want the installation.
The Board of Airline Representatives then makes the decision on whether the installation will go ahead after receiving the replies from the airlines and informs Airservices the decision the airlines have made.
So the short answer is if the airlines want a navaid they can have it - but at a price. In the end the airline accountants make the decision on economics taking into account the relevant factors.
Can you imagine the screams from the airlines if an airport operator just kept installing equipment that the airlines deemed unsuitable and had to pay for!! So it really has nothing to do with the airport operator but the airlines themselves.
It is fairly hard to justify a CAT III installation on economics in Australia as the number of occasions that the ceiling/visibility would require CAT III operations is extremely low. This was using Bureau of Meteorology data.