I don't think anyone would be expecting a quick turn around if SE announced it. That would likely be the biggest shock from them is if they announced it and had it ready within two years because they had already been working on it. Yet with all of their past releases, it's very unlikely seeing how I'm sure their priority has been finishing the XV DLC, getting KHIII and VIIR out the door, and working on Shadowbringers for XIV has likely absorbed most of their main teams. Not to mention we've also seen a bunch of smaller and medium releases as well. A XVI announcement would likely have a tentative release date of 2024 or 2025.