Yeah I have noticed this as well. Now, this is just a hunch, but I am pretty sure people aren't logging out for days on end because of one core reason. The longer you stayed logged into the game, the higher your resource gains are able to climb.
For example if I was getting like 50 to 90 gold in my main town, if I leave it run over night when I wake up my gold is now 300 or higher per "tick" which I have yet to figure out the tick rate. I am assuming that it is on a per day timer or every 24 mins? But anyways I left the game run for like a few days and I was getting like THOUSANDS of resources and money per tick. Now, I don't think the numbers listed were accurate, but I did get a few screenshots at the peak.