Think about other engineering disciplines - "okay" engineers can build new bridges, great engineers can cheaply fix existing bridges so they never fail again. It is the same with software. Good engineers make new programs, and whenever they see a problem, they start from scratch, wasting time and money. Great engineers massage existing code into something amazing, increasing efficiency without breaking the bank.
As a side effect, if you make something crappy more reliable, it makes the creator look bad, as they should. Otherwise, you will look bad.