>> Atlassian is probably a fair bit away from that.
How do you justify that?
One way Atlassian's market size gets limited is by being viewed as a competitor to Microsoft (or other large incumbent's) products. Some customers can choose both, but not everyone can. The feature and experience differences don't matter much to the buyers (procurement), so if something is cheaper elsewhere, then it's a harder sell. It also increases risk in a potential recession where Atlassian is viewed as a luxury option. I feel like JetBrains play a smarter game here.
It feels like folks have forgotten how bad a niche developer tools have been. Circumstances have meant that VCs have been throwing money at developer tools and developer experience has been in vogue. Things will probably be better in this wave than previous ones, but it's still much riskier than other markets. Developers may rule the world, but the software powering their day-to-day is very different between software companies and the majority building line-of-business software.