You are all assuming that there is only a grindy way of training firemaking. There's more than one way to get xp without click click clicking logs for days. People can light the torches in mort myre swamps, light beacons around runescape and the wilderness or by using the blast furnace. Not everyone is obsessed with efficiency iand there are bound to be at least some people that will enjoy lighting beacons in order to level up their firemaking to be able to do the quest. Players are also free to use up any lamps, books, jot, penguin points, dragonkin lamsp and troll invasion exp on firemaking too. I welcome the level 90 requirement even if it is in a less "important" skill.