I’m certain that Jagex wasn’t necessarily doing that out of the kindness of their hearts. RuneScape community sites have had a history of advertisements that border on malware at worst, are paid phishing attempts at best, and benevolently full of grey market account services and real world trading platforms.
Best case scenario was them hosting the platform to protect the integrity of their game, and the community.
Not to distract from the good move that it was, of course.