It's like the contractor (or subcontractor) who built the house you live in. They don't have to pay your monthly heating or cooling bills, so they often do what

It's like the contractor (or subcontractor) who built the house you live in. They don't have to pay your monthly heating or cooling bills, so they often do whatever is fastest and cheapest for them. Who cares if they didn't insulate a wall correctly or put an inefficient system in? If they can get it by the inspector, they will do it. If they can save themselves $100, that is all that matters to them. Who cares if it adds $10 to each month's utility bills for the next 30 years? They got their money and are now long gone.