To US ears that might sound unbelievable, how can you not have heard these songs, but that's like me saying how can you not know the songs of Evert Taube, Cornelis Wreeswijk or Lasse Berghagen, when Swedish music is so internationally famous.
You have heard ABBA, Ace of Base and Roxette, because those are the things that went on export, but there's a load of things that never did, that are deeply Swedish and didn't make the slightest effort to appeal to an international audience.
Dylan, Seeger and Guthrie are not the Madonnas and Michael Jacksons that the record companies fed to Europeans, and which were understandable and consumable without that deep US context. Dylan is the best known of them outside the US, but still niche.