Why are some skins left in Limbo with no recall animation??

Right around the time when Riot stepped up the quality of their skins, a bunch of skins missed recall animations. To name a few, Astronautilus, Arclight Varus, Warring Kingdoms J4/Xin etc. Are they never going to get a recall animation? Some of these skins got bumped up to 1350 once you added that as a pricing for skins, which never made much sense considering they lack a standard feature which even 975 skins get.