Melbourne is a great tech hub, but nothing compared to SF, SEA Aand NY. There is no real way to get funding from public investors, you have to talk to "old money" (though this was a couple of years ago, this may have changed).
There was a great article I read a while back talking about Atlassian's move from AUS to USA.
When they were starting up JIRA they had to do it from $10k credit card debt. No investors in Australia wanted to touch them. So they moved to the USA and got funding almost immediately.
From memory Atlassian was profitable very early on. I'm not sure what's wrong with investors there. A lot of our economy is run from raw materials, so maybe they just don't get it?
EDIT:
My experience is that software engineers are very intelligent there. I've worked with a lot of smart people in the gaming industry and mobile.
The issue is a lack of leadership and funding.
Both founders still live in Australia. Roughly half our global staff are Australian.
These days with local VC funds you can get funding much easier than when we started. That said, for later rounds (>150m+ valuation, tens of millions of dollars in), you are likely to get a better deal from the USA firms.
Scott, founder Atlassian
Atlassian did take money, but was actually quite far down the road. Something like 7 or 8 years in. Even then it wasn't a very standard VC deal. They're naturally a global company, but they're still very much an Australian company -- so I don't think the moving from AU to US for funding narrative is representative (or really generalizable for other AU startups).
I totally agree there is lots of good technical talent in Australia. As good as anywhere, but the culture of risks and startups is only just starting to germinate. Seems to be taking root now though.