Why does npm add so many folders to the node_modules folder?

It very well could be. gulp-concat might have a few dependencies, which have a few dependencies, which have a few dependencies.

So while gulp-concat might not have 163 diredt dependencies, if you followed the dependencies of the dependencies, it might be. I'm only speculating here.

And thus, that's the beauty of the node package manager. As developers, we get to completely free ourselves from this dependency hell, and let npm do it's job, which is mange the packages.

Npm is only going to download what is necessary, based on the package.json file in each package. I wouldn't worry about bloat, as that's the beauty of a node_modules folder, no framework should, or if not using a framework, you shouldn't load the entirety of the node_modules folder into an application. The packages should, and likely all do fall around import and exports.

Meaning, packages to do something, export that function as a module. And packages that depend on a dependency, import the module from the dependency. All that to say even though you end up with a lot of folders, you application is only pulling out what it needs, to function.

You shouldn't even be checking the node_modules folder into git. The package.json file is enough to rebuild that folder by another developer, or on another machine.

Don't worry, my most recent project, I have only added about 6 packages myself, but those packages dependencies have added about 110 folders in my node_modules folder, which I truthfully almost never look in.