And it's really easy to amass items to get into Advanced Quests, especially when you can trade in As and Bs to get C, D, E, Fs.
I also remember getting to 50 SMN in FFXIV within 3 days of its launch in 2013. I mostly pulled it off by doing Boss FATEs with Topaz Carby/Titan-Egi, because it was still a tank pet, and we had Sustain. It could solo pretty much all non-group boss FATEs. In addition, on its release, DPS and healer were in need for weeks in the duty finders, not tank. I stopped doing story for a while because of issues with the duty server due to unprecedented high server load due to all the players and Square Enix not thinking there would be so many people.
Every time an expansion came out, server load would skyrocket to the point of them nearly crashing, so they had to limit the amount of people who could login, and put them into a login queue. Not to mention, they would add an auto-kick system to remove AFKers from the game during the initial couple weeks when an expansion released.
All of this caused people who stayed in the servers to get ahead of those who could not get into the servers. Which is why I'm still a bit peeved on PC version not coming out yet. I'm going to be going on a server that has yet to have a community, so SEGA can't use the "we want the servers to have a community and market before we let people in" excuse that FFXIV used to separate legacy players from normal players.