There feels no point in keeping the miners or villagers alive because the knight is vital for keeping for prolonging the kingdom's life. "Strategy" is too simple: focus on the knight, or else everyone dies.
Although I see the numbers increase, I cannot find any incentive to keep upping them. For the sequel to this game, I hope you add the option to hire more kingdom peeps (i.e. defenders, miners) by spending materials to deploy them. This would make the strategy more interesting because you would need to decide whether to prioritise your mining or your defences!