Why doesn't Australia introduce lions or tigers to fill the ecological niche of top predators?

This requires a correction of a concept: the reason why invasive species become rampant is not due to the lack of natural enemies, but because invasive species have gained a decisive advantage in competition with native species occupying the same ecological niche.

Subsequently, Australia introduced natural predators of rabbits to control their population, including deliberately introduced foxes, and wild dogs and cats that escaped from captivity. But what was the result? The rabbit population continued to thrive, while native herbivores suffered. According to a 2020 report, foxes have caused the extinction of 20 species of wildlife in Australia and have put another 43 species at risk of extinction. The reason is simple: if you put yourself in the position of a fox, would you choose to expend a lot of energy hunting for alert, agile, fast-running, and burrowing rabbits? Or would you choose to eat Australia's native, adorable, slow-moving, and less resistant koalas, wombats, sea turtles, and kākāpōs?

In fact, Australia does have carnivorous animals. Although the well-known thylacine and thylacine wolf have gone extinct, leaving Australia without large carnivores and leading to an overabundance of kangaroos, there are still small carnivorous animals, such as the Tasmanian devil—also known as the Tasmanian wolf. Although the population of the devil has sharply declined since the 1990s due to facial cancer, there were once 250,000 individuals in the 1980s. The key issue is that devils also prefer to prey on native species that are adorable and slow-moving, with little resistance, and they have not had a significant effect on controlling rabbit populations. Imagine if Australia did not have those native herbivores; with the help of devils, wild dogs, foxes, and cats, rabbits would find it difficult to run rampant. Therefore, to solve the problem of invasive species, it is not enough to simply introduce natural enemies.

The fundamental reason for the proliferation of invasive species is that they have won the competition with native species occupying the same ecological niche. To address the issue of invasive species, it is necessary to rely on strong human intervention, such as vigorously developing the rabbit meat and fur industry, making money while precisely regulating.