You aren't taking everything in to count here, for starters a good percentage of the guild is recycled players that play on/off at different times, meaning the players at 6PM have a chance of being different than the players at like 10PM. This meaning while some members are online others are offline doing other activities or sleeping, another thing to take into count is the fact the guild has young teenagers in it so even if they aren't on Graal there isn't much of a social life for them to have anyways, and lastly I know some of the people in the guild who are adults like Connor for example who has 18,000 hours yet he still has a balanced social and work life.

So technically, no it isn't two years of straight towering because the members will always be different at different times (aside from a few people who maybe play alot, but there is nothing wrong with preferring an online social life over a real life one)