You're asking about `angular-cli`, but I see the same question all the time in regards to Create-React-App. I'll paste in my standard answer on that topic:

The set of dependencies that CRA uses includes:

- A compiler

- A bundler/linker

- An optimizing minifier

- A linter

- A development server with live reloading

- A test runner

All of those are isolated and scoped to that one project, and they are all build-time dependencies only. It's also important to understand that Javascript packages are effectively distributed as source, which affects the number of files on disk. (Granted, many NPM packages do include unnecessary files in the published artifacts, but Javascript itself is a major factor there.)

Meanwhile, XCode is supposedly something like 8GB installed, Visual Studio is multiple gigs, and if you were to look at the actual file size on disk of any C++ compiler toolchain, that would be a minimum of several dozen megs - those are just usually preinstalled on Linux or Mac systems.

So, context is pretty important here. 70MB for a complete JS build toolchain is perfectly fine :)