OK, I'll bite ...
If RuneQuest were GnomeMurdered, Glorantha wouldn't recognize the threat at first. While everyone else is poncing about with their Hero Wars, the gnomes would stealthily kill important figures first, exploiting their small size, their resemblance to Dwarfs, and name confusion with earth elementals. By the time the warring cults and cultures realized what was going on, it would be far too late to do anything. All would slide inexorably toward oblivion, even Chaos itself.
If GURPS were GnomeMurdered, all the Infinite Worlds would soon face the gnomish scourge. Every being, from the 25-point weakling to the 500-point demigod, would face the same horrible choice: do nothing and let the worlds slide into ruin, or gamble on their advantages, skills, and techniques. For, if they roll the dice and fail, they will surely be murdered by a gnome.