I'm not understanding this problem people keep having not being able to get things done. The only explanation I have is that you need a better linkshell.

I've taken my fair share of breaks from the game for various reasons. Each time I come back, the rest of the player base is far ahead of me. But I have shellmates that are willing to bring me up to speed each time.

I just came back a few days ago, and in the first night I was back, my shell helped me unlock PLD, finish all the quests, including Into the Dark, and we still had enough time to help someone to help with 2 WHM quests, the BLM final quest, beat the level 25 Ifrit, farm tapers and beat the Hard Mode Ifrit. In the time that nobody was available, I ranked up in my GC and caught myself up on storyline quests.

It all comes down to finding a reliable group of friends and/or a linkshell with people who are willing to help.