I might be uninformed but it seems to be "everything is a file" was more or less true when UNIX was created, and then it evolved outside of the academic garden,

I might be uninformed but it seems to be "everything is a file" was more or less true when UNIX was created, and then it evolved outside of the academic garden, especially Linux which was a hobbyist project and never strove to have a cleanly designed, rigorous architecture. Plan 9 does fix this, and I wish so much it managed to be a dominant OS. So many things seem correct. Maybe it's exactly because it isn't used for real use cases that it can maintain its appearance of good design