That may be the case in some places, but certainly not everywhere. One of the public companies I've worked with uses Oracle to the tune of several million per

That may be the case in some places, but certainly not everywhere. One of the public companies I've worked with uses Oracle to the tune of several million per year in licensing fees. The CEO is responsible for maximizing shareholder value and he's not stupid - he approves the checks to vendors and knows very well that a single company accounts for an overwhelming percentage of their annual software costs. Therefore they are actively looking for alternatives where the cost-benefit ratio of switching is favorable. Heck, they would be negligent not to investigate ways to reduce their costs on behalf of the shareholders.