Canada has big fires as well. They're a natural part of the environment. The dominant tree species in northern Canada in fact require fire as part of their natural reproductive cycle.
What makes one fire worse than another is often more a matter of where it is than how big it is. A fire burning in an area where nobody lives is primarily an matter of the value of the loss of harvestable timber. When they affect inhabited areas then that's when the big problems start to stack up. When you get a big fire the main effort tends to focus on trying to keep it away from property, because it's hopeless to expect to extinguish the main blaze.
Man made factors can affect fires, but it's a complex issue with many natural factors coming into play as well. You get a really bad year when a number of those factors line up together.
There are things that Australia can do to mitigate the effects that fire will have on people, but they'll always have fires unless the place turns into more of a desert than it already is.
Ack all your points, but harvesting timber is frowned on these days. It still happens but is getting less common and rare in 'old growth' forests where the big timber won't grow any bigger. Timber harvesting of course leads to tracks being maintained and the under-storey being cleared.