I have read an interesting post which claims that in the cloud computing era poor performance directly converts to higher operational costs. http://www.infoq.com/news/2009/11/Price-for-Performance
I agree with this to some extent. Paying for machines is not exactly as paying for CPU but the general idea is interesting.
Thinking about it a bit more it makes me wonder that it will be nice to be able to find the equilibrium point of performance investigation investment. The amount of money that you invest of performization should be less than the amount of time you loose for inefficiency.
A new research area is born :-)