I’m not sure this can be claimed to be a thing. I mean, yeah, World Events were created to replace Raid/Invasion after their conclusions, and Raid/Invasion were meant to be completable with a Tier 3/4 buy-in… but idk. I think that was just for a Raid/Invasion. I’m not saying I want t6+ buy-ins, I just don’t necessarily think the Devs are honour-bound to it based on this statement:
World Events are a new thing, and the Devs can make them as unreasonable as they want .