What really accentuates the people’s refusal to help Kane ...
... is that the ending shows that, together, they could have easily dispatched Miller and the others.
Kane himself took out 2 of them, and his wife helped him kill the other 2.
If Kane and his wife alone were able to finish the job, then imagine if Kane had the whole town behind him? They would have won easily. That really drives home the point that the townspeople betrayed him; they were afraid for nothing