There was already trading going on in the top end of course, with the Macassans. But for all intents and purposes, the continent is a f**king desert in the middle of nowhere. No-one in their right mind would have wanted it that badly.
The Dutch had landed on the west coast, and then left it the hell alone. The French were sniffing around too, but didn't really seem bothered either. The Japaense tried it on in WWII, but I get the sense at the time their leadership was a little bat shit crazy.
The French were next in line, but the British got here first.
The Japanese didn't get here only because dare I say it, British colonisation 160 odd years earlier. Long term they likely wouldn't have been around long though as it turns out.
I think there is little chance the continent doesn't get invaded at some point given the land size and natural resources on offer here in any case.
If it for whatever unbelievable reason it doesn't get invaded, I suspect you would see a country comparable to PNG now. However, I suspect PNG is only as good as it is due to the fact that it was previously colonised, and the continent it is only a short boat ride away from is a pretty advance place, due purely and simply to colonisation.
Does anyone seriously think the USA becomes the super power it became if it was left solely to the indigenous people there without colonisation?