This, in the end, was what completely broke my enjoyment of the second game.
To be immersed in a world, you have to believe in it. But anyone with the tiniest knowledge of oxidization and neuroscience can't possibly believe for a moment that BS2's timeline makes any sense. The suspension of disbelief is completely ruined by the fact that the city is still there at all. It's not that Rapture itself is too unbelievable; rather, it's the idea that somehow, without ANY maintenance whatsoever and constant conflicts/explosions occurring inside it, that Rapture is even still standing after ten long years of violent destruction.
Actually...it is believable, especially since BioShock 2: Minerva's Den actually addresses this specifically.
The Thinker is an automated central computer that is still running, continually analyzing the city and what is happening in it, and also performing maintenance throughout the city with various machines....and even then, it can't keep up, and the city is indeed falling apart on itself....just not as fast as a city that is completely left alone to rot, since, as I said, the Thinker still has machines performing different maintenance tasks throughout the city.
This isn't even taking into account some of the survivors or even splicers who have crafted out their own living areas in the city, which I'm sure they maintain in some fashion....especially given the visual evidence throughout the game.