I honestly don't know. I didn't die before coming here so I wouldn't fit that theory myself. But I think there's something to be said about we can do things here we couldn't do at home in general.
The days had been getting shorter even when I was a kid with the increase of daemon activity. They released this thing called miasma which absorbed daylight. After Prince Noctis went into the crystal we quickly lost the daylight we did have. Kind of like a virus too in a way. It would infect people and turn them into daemons and feed into the system making everything bad.