100' is, like any rope, either too long or too short. It's hardly outrageous. As noted above, it depends on the purpose of the kit, the terrain, and the anticipated circumstances.

It could be quadrupled to help get a quad or small vehicle out of a rut. That eats up footage in a hurry, especially when you add knots.

Or, a longer line could permit water and warm clothing to be lowered to a person who is trapped on a ledge and awaiting rescue.

Generally speaking, for any backpack kit to be carried on foot, it's absolutely critical that the list-maker take it for a 5-10 mile schlep. This focuses the mind wonderfully, leading to all sorts of efficiencies.