I agree with the rest, they've all mostly lost market share or completely no longer exist due to VS Code, but not IntelliJ, that platform is going really strong.
Though no doubt, VS Code has pushed JetBrains to rethink some things, and be better in general.
They can have all the money in the world and it doesn't mean much in this context.
For while Microsoft is going to invest heavily in a Cursor / Windsurf like product and likely do alot to ship it in their editors - likely with exclusions or lag times between updates on other platforms - there's zero reason for Google to do this for example, when they could sell through Gemini for Code as an extension across all editors.
I don't see JetBrains having issues because of AI tooling, for most of these companies, its a boon to be on the JetBrains platform. Especially because JetBrains has lots of enterprise customers who would naturally be very interested in buying AI tooling for their developers. Its a natural market
vs-code is one of the few products coming of of microsoft that leads the pack by a big margin, and it is no surprise that all of these startups are forking it.
One exception in 50 years does not inspire confidence.