Oh definitely! They didn't really have any direction for story early on, but with Mahjarrat storylines that began to change. Then they began to weave all the different stories together into a coherent world with surprising success.

I'd say in 2011-2013 the story really started to kick off. Gods for example were turned from simple good-evil entities into actually interesting characters representing different ideologies and philosophies.

Unlike some other MMOs, RS doesn't have voice acting (for the most part), which allows them to write a lot more dialogue. For example Azzanadra's Quest alone has ~25 000 words of dialogue. You can probably imagine how much lore a 20-year-old game like that can contain!