Profitability = Functionality + Manageability
Functionality is directly visible to customers, it's what provides value to our clients and revenue for us.
Functionality obviously affects revenue and profit and it's easy for everyone to see and talk about (executives, managers, customers, testers, etc.).
Functionality is only half of the equation.
Project and code manageability is less visible and is often ignored, especially in terms of the bottom line.
Manageability makes code easier to understand and thus to modify quickly and reliably, it reduces the cost of producing functionality-rich software.
Therefore, individual performance and project success must to be measured in terms of maintainability just as much as on business functionality.