While it would be a neat concept to have things scale up to us at all times that would require a different coding completely and it would require a whole lot more balancing. The fact that they would have to completely recode everything from ARR to ShB alone makes it an unreasonable and daunting task. Then instead of balancing these dungeons, fates, trials, and instances of the like to a single specific small level range they would have to balance them all to every level there is, and then do it again every time the level cap is increased. Once more, this makes the task unreasonable and daunting for no real reason when their time could be better spent elsewhere like continuing to streamline ARR, working on new features, fixing Hrothgar, and all sorts of other things.