Microsoft's Command Shell zoo

Can Microsoft explain why they have to have at least seven different command prompts, each with different commands, for developers? In addition to the ones in this picture there is also the regular command prompt, PowerShell, the Package Manager console, and probably a bunch I don't even know about. In *nix there is one command prompt: the bash shell (unless you're an uber-geek who's installed some exotic shell on your own). Okay, there's the SQL prompt, but that's like a completely different program. Whose job is it at MS to make things unnecessarily hard?