There are organizations that operate like families, and there are organizations that operate like big corporations or machines. In the latter, employees are like cogs in the wheel, necessary for operation of the machine, but that's it. In some organizations, employees are treated like liabilities, not like the assets they really are. It sounds like you've experienced the latter, and now that you know what you get when you work there, either you accept it when you take a job there, or turn down the offers.
Everyone is expendable. We have to be, or theatres couldn't continue to operate, past our association with them. Some organizations just like to call attention to that, more than others. As AEA SMs, we have agreed to work on a contract to contract basis. There is no "tenure" inherent in this system, so why are you expecting it? The organization owes us nothing past our present contract. In fact, the late Artistic Director of a major regional theatre in this country used to say, "Stage Managers are not part of the process." Every organization has their own philosophy and own way of operating, We are not in control of the behavior of others.
If your own ego needs more stroking, beyond the good feeling you get when you do the job well, then don't work there anymore. They are not going to stroke you, THEY are not going to change. Perhaps your own expectations need examining. Either that or you need to find a company that offers what you need.