Either EU got insane server capacity or there weren't enough players to make the queues we had on Endwalker launch. I would say Sproutbringer ended somewhere after Endwalker. People did the MSQ, Dragonflght got announced and they switched. Long-term relationships and addiction are still there. And as the expansion was somewhat good it didn't manage to regain all of the players lost (underperformed on sales and subs than what they expected) it started a trend and with Metzen here and there people probably now will go play War Within launch. FFXIV won't have any significant content until the next expansion anyway unless someone wants to clear all the tiers. WoW at least is capable of big change each expansion, especially when their playerbase hits rock bottom from bad content