Technically, BS Zelda no Densetsu [1] is a re-release with updated graphics, but I see your point. I believe Zelda 1 & 2 gameplay do not translate well to modern audiences, so it's easier to just re-release them in their original form instead of merely updating textures or going for an all-new remake. Link's Awakening was a much fitter candidate for the latter.
By the way, the Oracle games were originally intended to be a remake of Zelda 1 [2].