Andy, as you have mentioned there are so many factors involved, and every person will have a different view.
I always use Herzberg’s two-factor theory as a starting point during these types of discussions ().
The harsh reality is that the goal of any company is to make a profit and to create wealth for the shareholders.
Your company’s goals might not always be in line with your personal goals.
That does not necessarily mean that you will not get job satisfaction.
I have heard about a well-known company where many employees have complained in public about the working conditions; yet, new employees are literary trampling over each other to get job interviews.
Personally I believe that when the job becomes too repetitive and you are not learning anything new, it might be time to start looking elsewhere.