Hidden Relicsaid: That's what the community ASKED for, for them to spend time focusing on improving and updating existing content.
Even if the community asked for such a greater focus on improvements and updates to existing content, one of the most requested updates, if not the most requested, bank rework, was outright cancelled, after it was being used to sell memberships since 2016.
But no, like Recursion93 says, Jagex has been very much able to do both, new content and patches, almost weekly in the past (there are exceptions of course, and as long as they remain exceptions, that's fine, but patch weeks have become more and more common, which is not fine). After they started aggressively selling MTX, claiming that it'd improve the quality and quantity of the game updates, the opposite happened. So if they intend to keep their monetization going like this, it's only fair to expect them to deliver at least the same level of quality and quantity as they used to before the monetization increases.