Why Should We Not Celebrate Low Costs?

Is a lower cost to consumers the right way to measure the total impact of value created by this company? When i was a senior partner in strategy, i did a lot of work for governments involved in restructuring major telecoms companies, oil companies and so on. The central rule that followed through at that time was that if a murger led to a lowering of costs, it's good that's being challenged today. Why should we not celebrate them?