So I had an interesting thought regarding the Day of Lavos in 1999, the post-apocalypse in 2300 AD, and the fate of the planet itself afterward.
In Arris Dome, the party recovers some seeds from the basement and presents them to the people above, telling them that the seeds "could be their last hope" if the enertron fails. For the first time in possibly over a hundred years, Doan and the others become a little more optimistic, and "The Day The World Revived" begins to play.
..."the day the world revived..." That's what I'm curious about. What if it really did?
So, obviously there are a few obstacles at play, here. Time, robots, mutants, crap weather, etc. Given the game's themes of dreams, determination, and perspective on life, is it that hard to imagine a *tiny* population of humans surviving and slowly repopulating the Earth? What if the party found a gate going even further ahead, say 5,000 years? 10,000 years? Would the planet actually be far more habitable?
If you revisit Arris Dome later in the game, Doan will remark that, of all things, the seeds they planted are actually beginning to sprout. So, the soil is not infertile. After awhile, the seed very well could bear fruit, and thus Arris Dome could eventually gain a small garden. A garden of what exactly?? Unknown - if they are a mixed variety of a seeds though, there might be some survival essentials. It wouldn't be easy, but it is possible that not only could Arris Dome eventually become a functioning greenhouse with a healthy staff, but more healthy people could brave the ruins and set up greenhouses at other domes.
As for Lavos? It's mentioned that in the future Lavos is leeching off the earth, slowly killing it. Thing is, it has already begun to produce children which will soon leave the planet. After that, it seems reasonable to assume Lavos will probably simply die off on its own. It might not survive long enough to completely kill the planet, especially when that planet clearly still has fertile soil and is capable of at least growing food.
So, greenhouses start cropping up at domes, people get healthier, heck maybe even some repairs are done over the decades/centuries. Maybe even more unique seeds are discovered/planted? The machines try to stop them, and might set them back a little bit, but Mother Brain I think mentioned that part of the plan hinged on humanity becoming weak. That is starting to not be the case. Scrappy little humanity, the race chosen in prehistory for being tough survivors, manages just that. It wins out against the robots, and ekes out its own survival against the mutants as well. Eventually, the dust clouds over earth will settle, and though Earth *might* not be the same ever again, it at least might become something new. Ultimately, the Day of Lavos is no worse to humanity than the ice age, or the world post-fall of Zeal...
...aside from possibly saving other worlds from suffering the same fate as their own, as well as paving the way for the foundation of Chronopolis, the rest of the game might not have even been necessary.