TBH I would prefer merging pnpm to npm instead. I don't see any reason to further promote Yarn which is already overrated. The concept of linking packages existed long before Yarn. First commit to Yarn was on Jan 23, 2016. The concept of linking packages was introduced by Alexander Gugel in the ied package, first commit on Aug 6, 2015. Approximately half year later Rico Sta. Cruz has created pnpm which was pretty similar to ied but with better npm compatibility. Creators of Yarn did know about the possibility to use symlinks and links. You can search in their repo for discussions about it. They discussed the possibility of using symlinks back when Yarn was not public and due to many reasons decided not to use symlinks.