I would not be surprised if the market share breakdown is similar to browsers (eg 70+ percent - more if you ignore that safari is the only real option on iOS).
VSCode has slowly been getting more and more bloated, but the alternatives are all very meh or are missing crucial extensions.
If you do embedded development, things like https://platformio.org/platformio-ide, but also smaller, nice to have extensions for auto-deploying code to cloud providers, etc.
To me that sounds like claiming Arduino IDE is a "crucial extension". Their website[1] lists a bunch of IDEs where it can be integrated, so I wouldn't call it missing. That said both of these are hobbyist toys to make it more approachable and embedded development was fine long before VSCode, they're in no way "crucial".
VSCode has slowly been getting more and more bloated, but the alternatives are all very meh or are missing crucial extensions.