A tower at Mildura would quite feasible if the aerodrome owner thought it would enhance safety at their aerodrome and entice new businesses to invest there. After all the airspace around an aerodrome should be considered as one of the assets used by the aerodrome to carry out it's business.
In a free-enterprise country it should be possible for the aerodrome to decide that it wants a controlled environment, and in accordance with ICAO requirements, go ahead an build a control tower and employ people to work there.
Unfortunately they cannot - decisions about such things are made by CASA in accordance with the wishes of the Minister (National Party - Mr McCormack). The aerodrome operator and people who fly there are merely "stakeholders". Basically unless an aerodrome passes one of the CASA milestones (See the Australian Airspace Policy Statement from the Minister) CASA will not consider mandating ATC.
This means that aerodromes that would benefit from providing a tower in order to build up a business, can only do so if A) CASA agrees, and B) Airservices agrees. (Don't be sidetracked by talk of digital towers, compared to a glass box on stilts with one controller looking after the circuit area, digital is prohibitively expensive). While CASA may be convinced, they are only a small part of the aviation scene. Because Airservices cost-recovers its services then the majority payers such as Qantas get to decide what Airservices spends their money on - and I can almost guarantee a control tower at Mildura is not even on the bottom half of their list.
It is past time that Australia threw off this stranglehold Government has over civil aviation and let the industry operate in a competitive, albeit with safety regulations, manner.
This post is only one example of where change can take place quite safely if the politicians started to get the right advice.