Using engagement metrics as a KPI is the problem. That's exactly what led WoW to Shadowlands. If a high percentage of the remaining players are engaging with Cosmic Exploration and Occult Crescent, that doesn't necessarily mean that it's good or fun. It could very well mean that players are all but being forced to do it for power progression (Torghast), or that it's the only relevant piece of content in the game that hasn't already been completely exhausted (CE and OC).

They need to ditch the formula, stop thinking about FFXIV as a series of quantifiable deliverables, and start making a game again. The name Creative Business Unit 3 is almost ironic at this point. FFXIV's development is more akin to a factory conveyor belt than a creative process.

The percentage of the playerbase that is engaging with a piece of content is not important. It's important that content is enjoyable for players who are fans of that type of content and that the game continues to deliver new and interesting experiences.