Which is fine. RuneScape has been in development since the early 2000s, long before GenAI even existed. They got along before GenAI and they can continue to not use it.
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.