I'm not sure what more is required to make it truly open.
Once Jetbrains no longer controls Kotlin's future and most Kotlin users are not Jetbrains customers, then I'd consider it truly open.
Are you upset for the election in USA?
VS Code is miles ahead of Jetbrains offerings and has no yearly subscription fee.
MS was indeed one of my least favorite companies half a lifetime ago, but they've changed business models and are now pursuing a growth strategy (particularly wrt services) and have abandoned the fight to capture consumer surplus at all costs.
I've gladly purchased Jetbrains products in the past (and other dev tools as well). Noticing that a company is intent on capturing all consumer surplus they possibly can and disliking them for it is not the same as deciding they're "evil" for charging anything to begin with. Before moving to their subscription / hostageware "pay up or be forcibly downgraded model", I happily broke out the credit card and paid for Jetbrains offerings. I don't begrudge them that they sell software.
They just got too greedy and consumer backlash like this is the inevitable result.
And yeah don't forget Eclipse Kotlin plugin, fully open-sourced)
JetBrains open-sourced decades of their hard work, building world's best IDE. And you can benefit from it for free.
You don't even have to pay for webstorm/rubymine. Just install plugins you need to Intellij CE)))
UPD. When I pay for their job, I receive real stuff and not some obfuscated shit. The stuff that will be compiling even when the subscription ends.
What happened? Could you please elaborate?
On the other hand, it's controlled by Jetbrains—the company that now offers a "yearly license" of many of its compilers at the same price point it once sold them for, after which time they forcibly downgrade the software their users have paid for. It's not illegal and some even agree with the practice on an ethical level, but it's clear that Jetbrains is all about hoarding as much consumer surplus for themselves as they can.
If only Kotlin were truly an open project and well supported outside of the Jetbrains marketplace, e.g. by VS Code, I'd be cheering it on.
-former webstorm/rubymine customer