I think the fundamental flaw in this argument is that you’re staking that the island is more important than its inhabitants.
The islands may have been doomed from the start, but their inhabitants were not. Mask of Light saw the Matoran population return to their true home, albeit one they had no memory of, and from there returned to Spherus Magna once their mission was complete.
I can see your arguments are generally based on 2003 and prior. The answers to some of those questions were fleshed out down the line. For instance, the Toa couldn’t actually awaken Mata Nui because that had to occur in Karda Nui, and they had to get through Metru Nui in order to reach it. Plus, the Scroll of Awakening necessitated the evacuation of Mata Nui before his awakening, among other tasks.
Also, I don’t know if you’re new to the boards, but political/religious discussion isn’t allowed, so I’d steer away from those comparisons.