Completing a day of menial work tended to be the limit for an adult. It wasn't like Ren Xiaosu was trying to squeeze the most work out of them, so he didn't intend on tiring them out completely. He only wanted to make them tired enough so they would not have any energy to think about their own self-interest and start accepting a new realm of thoughts.
Some of the bandits would definitely adjust to this new mindset slowly, but there would also be some who were more stubborn and remain skeptical of all that was happening. But because of their fascination with getting into Stronghold 178, they decided to keep an eye on things for now.
Ren Xiaosu did not think he could control everyone else's behavior since he was not a god. But he was not in a hurry to convince them because he still had time.