There are numerous ways your work may be valuable. The easiest to measure is increasing revenue, but there is improving margins (reduce cost, but keep revenue), decreasing risk, improving retention etc etc.
Always try to figure out how what you or your team are building is contributing to the companies bottom line. And when you are in a team, you are part of that.
A very valid point. My advice was not clear enough. I have updated the original post with your comment and added:
"I was certainly not trying to be whiny. This is just business after all. I was just trying to point out how a single minded focus on costs without relation to benefits helps neither the company or you as a contractor. But just to be clear, my advice is to open up the conversation from just costs to a negotiation which includes other things, including the benefits."
I agree that businesses should always been looking at costs, but only in relation to the benefits. Just looking at costs and trying to reduce them is meaningless.