Current electricity generators are very frightened of investing huge money in a power station only to have it stopped and the money lost. Take Redbank Power station. Killed by Labor government.
If Liddell was shut down today the price of electricity would increase and it's present owner would make more money. Liddell was first commissioned in 1971 with a design life of 20 years. In 1988 a study did woyon what was required to extend the life to 2000. How it still operates I don't know. I know its output is severely reduced. They really don't care how energy is generated, they just want to be doing it. There is huge money in electricity.
In the 1990's Yalourn power was sold for a very large amount of money, the new English owners found that they were sold a pup, not nearly enough return on investment. On learning how much the Victorian government got for power station sale every other government wanted to sell their power stations. However there were no buyers as the buyers realised that there was not the profit in it. In NSW the government decided to make the power stations much more profitable. So renewing Poles an Wires was introduced. Substations the didn't have a power supply was built and power stations now had heaps of potential expansion installed and a huge increase in price of electricity from poles and wire increases. We essentially pay a tax for the money that the government got for the sale. They built a few gas turbine stations, none combined cycle (much better efficiency and less emissions per kWh) cheap and profit making. A few years ago the bulk price of electricity averaged out at $140/MWh, $0.14/kWh, I pay a lot more than that for retail power, nice little earner.
Some gas turbines are installed and don't get used until the price of electricity goes high (one I know does not operate until the price goes above $6,000/MWh). After all a gas turbine can go from Zero to full load in 10 minutes.
During the recent Queensland power failure the loss on power was made up by gas turbines just sitting and waiting for such a price rise. It went so high that a in 5hours the profit amounted to 10% of the gas turbine purchase price.