It is, but the statement goes further than that and says they use no gen ai at all in making their games. Which feels unnecessary, unless they mean just in the art and writing, which feels misleading
People may be forgetting the game has 20 years of content already, why do they need to make more faster with GenAI? Its already a massive piece of software.
Runescape is quite literally a dinner table name it is that famous. Their only true competition is probably World of Warcraft. The community is already huge. What competitive advantages are they going to lose? Likely none.