I am NOT writing about monetary expenses!
Of course you're not. Duh. I asked you to define what calamity you think will befall the player, which is why the word was in quotes.
Since you included "Pursuing one's own happiness at the "expense" of others." in your explanation, please explain how breeding villagers will hurt other people. Because it appears we have now gone from it hurting the player to it hurting unknown numbers of innocent bystanders.