So what? it's not important. It doesn't affect these people's ability to play the game.
Beyond that, I don't know ANYONE that 24/7/365 could NEVER log in at a different time of day ever for any reason.
Most of the time I log in, it will be evening. That doesn't mean I'll ever be able to log in during the day, it will happen sometimes. Beyond that, you can always pick a server in a different location if you really absolutely cannot ever 100% log in at the time of day you'd rather be on at. But I can't imagine many people having this issue.
Go play WoW for 5 minutes. Ask around if anyone cares what time of day it is in game. if you get more than one person to say they wish they could experience different times of day, i'd be extremely suprised.
Well, I give up on this. apparently people really love their eorzea time.