Two other sources for the distinction between kedushas ha’aretz and the “shem” Eretz Yisrael:
1) The Rambam writes (Rotzeiach 10:1) that eglah arufah can be performed only in Eretz Yisrael and Eiver haYarden. Even though Eiver haYarden has no kedushas ha’aretz (though see previous post here) it is still within the boundaries of land designated as belonging to Am Yisrael.
2) R’ Ahron Soloveitchik quoted the opinion of the Kaftor vaFerach that the issur of leaving Eretz Yisrael applies even to those places conquered by Yehoshua, whether or not they were re-conquered by Ezra. The Ramban similarly writes (beg of Gittin) that the concept of loving Eretz Yisrael extends even to those portions which have no kedushas ha’aretz but are part of the land promised to the Avos.