It’s because the majority of people who play this game don’t care about savage or ultimate and we are continually told this is a casual mmo, therefore, any tomes changes are most likely very low down the list, and the dev budget is more likely to be spent elsewhere. You bet that SE has a list of “content undertaken by the population and graded by percentage” and savage/ultimate is no doubt wayyyy down the list with Mogstation, glam, crafting and housing right at the top, because these activities pay the bills and create the profits, most likely.