This argument is a compelling case for JetBrains and I hope it proves out.
> They cannot lose interest or make self-destructive decisions because the IDEs are their core revenue stream.
But this can be said about Microsoft as well. IDEs are not the core of their revenue stream, but they're near the core, because "developers, developers, developers, developers" is still true. They're a software company, they make operating systems, a cloud platform, and hardware. They need to provide developer tooling. If IDEs aren't their core revenue, they're certainly near the core. If Microsoft hasn't been making money on IDEs lately, they have in the past, they see other people are, and they're certainly going to try and get back to that if they can.
That argument is true for Visual Studio. Not VS Code, which is Microsoft's "rewrite moment". Visual Studio is targeted at Windows apps, which you have to pay Microsoft to use. VS Code is targeted at web apps, which people run on Linux. The revenue impact is highly indirect: it's not like people will write more web apps than before now VS Code exists, somehow benefiting Azure.
They could try to do a reverse JetBrains and introduce an enhanced for-pay version. Supposedly they're already starting to do that with Python support, it seems. But starting commercial and going free is a lot easier than starting free and going commercial, in terms of user loyalty.
> They cannot lose interest or make self-destructive decisions because the IDEs are their core revenue stream.
But this can be said about Microsoft as well. IDEs are not the core of their revenue stream, but they're near the core, because "developers, developers, developers, developers" is still true. They're a software company, they make operating systems, a cloud platform, and hardware. They need to provide developer tooling. If IDEs aren't their core revenue, they're certainly near the core. If Microsoft hasn't been making money on IDEs lately, they have in the past, they see other people are, and they're certainly going to try and get back to that if they can.