How come AWS sometimes has even better tooling for .NET than Azure, while JetBrains offers better IDE on Linux, macOS and, depending on your taste, Windows than Microsoft? Or, for some reason, the most popular deployment target is just a container that is vendor-agnostic? Surely I must be missing something you don't.
All of that is absolutely true and in no way affects the behavior at hand. Big companies go with whoever sells them the best, not any kind of actual technical evaluation.
