The part that the cost of changing software is unknown, ignored and fixed is not true anymore. This is a thing I realized recently.

A company cannot get free (o low cost) software changes anymore. Someone invented llms and they charge by work produced (useful or not)

So a PM cannot "save" costs by pushing. The employees will resort to their agents and there will be cost. If there is no agent, another company will beat them. So now a change has a measurable cost and even you can calculate in what was spent (agent logs)