Earlier quoted context omitted.
The article talks about this. The problem is that growth is not there. What you're left is a company with 8000 employees and a system to problematic to change. With the recession incoming, the time for free money is over and tech startups are bound for a correction. I'd sell or get ready to wait 10-20 years. Even in the wait scenario, you're basically hoping that a huge corporation will transform itself and rediscove…
Atlassian isn't a US company, and if the US is going to have a recession (which I think is doubtful), Australia certainly has a good record on avoiding them.
And even if Australia is unaffected by an American recession, much of Europe, and much of Asia won't be (especially with China's growth slowing down).
Which brings me to my second point, which is the only reason Australia was able to avoid a US recession was selling itself to China, something which it is politically unlikely to do so anymore (although I'm not up to date on the new PM's China policy) and anyways, China may not have the capacity or willingness to support Australia anymore.