Let me go ahead and flex my MBA knowledge for all the engineers in the building who claim that MBAs don't know anything about business...
First, I suggest you read Atlassian's balance sheet and income statement. They're a public company, so it's all publicly available information. [1]
Look how fast those revenues are growing.
Look at how Cost of revenues is declining against the revenue. In 2019, it was 33%, 2020 it was 28%, 2021 it was 25%. That means that as Atlassian's subscriber count increases, its cost per subscriber is decreasing, a direct contradiction to the claims made in this article.
In the statements of cash flows, you'll see that Net cash provided by operating activities increases every year. Financing activities explain losses, not any sort of problem with the fundamentals of the business.
And, when you're losing money, you don't pay taxes. Atlassian is doing a standard business/accounting play here: re-invest in the business and use financial activities in order to pay nothing to the Australian equivalent of Uncle Sam. Income tax expense is a negative number on the balance sheet each year.
The worst claim in the article is that Atlassian represents a "legacy" product. No, not at all, especially if you've been on their cloud products anytime recently. The cloud products get rapid iterations and improvements, including performance.
Atlassian's pricing is extremely competitive, acting as a "bundle" that competitors can't match. Jira in particular has basically no realistic competitor, and OpsGenie does the same thing as PagerDuty at a fraction of the cost.
[1] https://s28.q4cdn.com/541786762/files/doc_financials/2021/ar...
(Scroll to page F-5 about 105 pages in)