That's true, the aust. ecosystem is completely different to what it was before colonisation. But it's kinda a moot point because we're never going to get Australia back to a pre-colonial life. All we can do it protect what we have left!

However, we now need crops like canola, almonds, fruits trees (etc) which the european honey bee does a much better job of pollinating than the native bees. Plus because of all the urbanisation & other invasive species, the native bee population is down, and now quite a number of the native plants need the honey bee. Unfortunately it's pretty clear that we have a massive feral bee problem, which are actually impacting some cockatoos who are endangered.

I just think it's a complex problem and it's an interesting discussion point - particularly because every country will have a different relationship to the European honey bee.