The point of Scrolls is that they are a thing which non-mages can use. As in, scrolls by definition, don't require you to have mage-like stats, so it makes sense that they do not use your stats and hence do not scale.
I can get behind that, but when a geo mage uses a geo scroll, the spell should take his geo stat and his intelligence into consideration.
If a warrior with 0 in geo and 10 intelligence uses the scroll, then it should do only his level as extra in damage.
It only makes sense to me that a mage can create a more powerful spell from a scroll than a warrior.