[azornathogron]

Various packages rely on node_modules existing as a directory with a particular layout, some rely on being able to write into it. Some of the npm alternatives are built to store and manage dependencies in other ways (e.g., keep packages as zip files or other archives and get node to load direct from the zip), and these other mechanisms do not use a node_modules directory, hence compatibility problems.

[michaelcampbell]

> these other mechanisms do not use a node_modules directory,

Once you've landed on a package manager that does use it, wouldn't you continue to use that?

[georgyo]

It doesn't matter if you decide to use a different package manager, if one of your dependencies depend on that layout, you must supply that layout.