Why do cost saving ideas not get done?

The degree to which companies are having to cut spending and budget expectation is directly proportionate to the degree of cost saving ideas that have been implemented. 
Gary Hamel startled me in his book, Leading the Revolution, many years ago when he pointed out the top line of ROI and the bottom line.
CFOs are risk adverse by the nature of their characters. Ideas push up their blood pressure. Why take a risk?
Let's keep cutting costs because I can cope with revenue payments but not with a new project face plant.

Of course, wisdom indicates that no one will save themselves to prosperity. But is does turn an umbrella into a shelter.