Just fixed the kingdom's economy. Honestly, I don't know why the King didn't just invest in these things.
While it is a bit of luck, this was my end game. I started out investing in curses and other units before investing into buildings and stat boosts to put my units up to 9/20 (which is typically when they become undefeatable in standard battles if they have a shield). Once I reached that point, I just farmed for the same building... which is easy since the building allows me to farm for more buildings, creating an endless loop of cash.
I don't think you understand how the minds of leaders work. That, or you think that the villain of this game is somehow different from our real world politicians and corporate executives.
I'm sure the king did invest in those. Probably had a lot more than that, even! More than could possibly fit on the entire field! ...and then he spent all of the income from them on food, wine, and other luxuries for himself. Well, what he physically could spend, anyway; he just hoarded the rest.