The expansion is winding down and the WoW exodus to FFXIV slowed with the release of Dragonflight because apparently it fixed a lot of the issues people had with that game. There's also been a ton of new amazing games released since Spring through to this Fall so people have been taking Yoshi P's advice to take a break and enjoy other games. Lastly, inflation was crazy and wages have not caught up. Many economies internationally have begun to enter a recession, the US while having avoided an outright recession (for now) has the average citizen completely leveraged between high rent / housing prices, credit card debt and auto debt being at all time highs, and student loan repayments beginning again. Childcare expenses have skyrocketed to the moon as well.

None of this is surprising. FFXIV will be in trouble if Dawntrail does not change somethings up but right now this is a normal trend given everything listed above.