… huh? Visual Studio is extremely not dead, they are literally about to release a 64-bit version after a massive rework. VS Code is a text editor which you can extend into being an IDE. Visual Studio is an IDE.
There are many reasons why one might be unable to upgrade to the latest version of any given thing. For an example close to my heart of why one might be unable to upgrade to .NET 6 (or indeed to later versions of the .NET 5 SDK), there's the showstopping https://github.com/NuGet/Home/issues/10389.