Of course it won't. But `bower-npm-install` and `bem` are required during development stage, only. For example, you don't need them on the production. So when you do something like this `npm install -g <path/to/pre/production>` from your project directory it would be strange to have all this development stuff there.

In other case, you can't move `bem-environ` and `bem-tech-core` to devDependencies, because it will forbid all the opportunities to use your project as bem-library (\bo tech limitations of bem-tools).