Throwing out a theory on how this whole raid could work out:

With all the focus on Time that's popped up with Shadowbringers, its not uncommon to hear people theorize time travel as a viable reason for things that are happening in the expansion.

I theorize (and something I haven't heard yet) that the whole YoRHa Alliance raid isn't just taking place in the setting of Automata. I'm thinking that the Raid will take place in the Far flung future of Eorzea/Hydaelyn/our world. As in a point in time so far from our own that the world has radically changed and the the events of all of FF14 is but a footnote in history. I'm assuming something in the future will pull us (and some NPC's) to the future either on accident or on purpose and eventually we re-awaken Hydaleyn's blessing or an echo or whatever in one of the YoRha/androids so we can leave that world with a new WoL to defend it.