Why would I do that when I unassigned almost 200 of them a few weeks ago?
What I *really* want to figure out is how I can get rid of them- permanently.
I didn't bring this up as any sort of bragging, just stating a fact and answering your question about why your ranking dropped.
It would cost me 726,110 gold to train all my idle workers. That would increase my score enough to put me in third place, however
it would take 450 "ticks" to get my money back from them. That's 450 ticks to break even, another 450 to return my kingdom's treasury to its current level. That's approximately 38 days of "real-time." Even longer if I did not put all of them in as gold miners.
I consider it highly unlikely that, if I were in third place, I would go long enough without being attacked that I would ever see a return on that investment. More likely, I would be attacked and would lose those workers (and the money spent training them) to enemy slavers.
Trained workers, once captured by the enemy, aid the enemy's war effort. Buildings, however, cannot be captured by the enemy. Yes, they can be destroyed- but never captured. Given the choice of what to invest in, I choose the option that cannot be used to my enemy's advantage.