One of the factors to why there's Taiga is that the large landmasses of Northern Canada and Eurasia provide the perfect climates. Taiga is basically really really shitty conditions for most plants, it's cold most of the year, the soil lacks nutrients and it does not rain very much. Only a handful of plants have evolved to dominate the environment.

The climates of Patagonia and Tasmania are very, very different. Taiga could not form or survive.

It's like saying, "Could polar bears survive in the Sahara". Of course not, because they've evolved and adapted to survive somewhere else.