To piggyback off this, another reason that I think software freedom is valuable is community support. Things like LSPs, syntax highlighters, and that sort of support doesn't have to wait on JetBrains to integrate it into their IDE. I think there is real value to the community being able to hack on a tool and not being at the whim of a single developer's priorities
Except for core functionality, everything in JetBrains' IDEs is written as plugins (grammar checking, themes, support for Go/PHP/Ruby/Python/Android/framework of the month, the list goes on). You just don't notice it because of good integration with the rest of the editor (unlike how it's done in Eclipse).
Those can be (and are) developed by anybody. For example, IDEA has had absolutely the best Rust story for many years, and the Rust plugin became official only recently. It was created and developed for years before that by a single developer not affiliated with JB (and still blew all other editors out of the water).
I just adapted the intellij-rust plugin from https://github.com/intellij-rust/intellij-rust to syntax highlight Rust slightly better. It works just fine, and I had to coordinate with nobody. Just edit file, build plugin, install plugin to the IDE (using the menu in the GUI interface). That's it.
Most of the stuff of Jetbrains is open source (under Apache Software License) and is available on github.
I know what you mean though: I would never again use a closed-source IDE, or a language with closed-source standard library. Microsoft Visual Studio made me learn that, decades ago.
You can also sell your plugins, but it does feel less "good" to be adding value to a commercial product that you're not a part of. By that, I mean there is somewhat of a sense of community around OSS that you can't replicate within a commercial space.
