The titular essay from this collection — which honestly you should just read — is an ambitious and candid discussion of the passing of his father during a time of great racial turmoil. It opens: "On the twenty-ninth of July, in 1943, my father died. On the same day, a few hours later, his last child was born. Over a month before this, while all our energies were concentrated in waiting for these events, there had been, in Detroit, one of the bloodiest race riots of the century. A few hours after my father's funeral, while he lay in state in the undertaker's chapel, a race riot broke out in Harlem. In the morning of the third of August, we drove my father through the graveyard through a wilderness of smashed glass."
Another important concept concerning all three curves is that their scope is the development of major release of a system. Following the traditional approach some systems are released once and then bug fixes are applied over time via patches. Other times an incremental approach is taken where major releases are developed and deployed every year or two. With an agile approach an incremental approach is typically taken although the release timeframe is often shorter - for example releases once a quarter or once every six months aren't uncommon, the important thing is that your release schedule reflects the needs of your users. Once the release of your system is in production the cost of change curve can change. Fixing errors in production is often expensive because the cost of change can become dominated by different issues. First, the costs to recover from a problem can be substantial if the error, which could very well be the result of a misunderstood requirement, corrupts a large amount of data. Or in the case of commercial software, or at least "customer facing" software that is used by the customers of your organization, the public humiliation of faulty software could be substantial (customers no longer trust you for example). Second, the cost to redeploy your system, as noted above, can be very large in some situations. Third, your strategy for dealing with errors affects the costs. If you decide to simply treat the change as a new requirement for a future release of the system, then the cost of change curve remains the same because you're now within the scope of a new release. However, some production defects need to be addressed right away, forcing you to do an interim patch, which can clearly be expensive. When you include the cost of interim patches into the curves my expectation is that Figure 1 will flatten out at the high level that it has reached and that both Figure 2 and Figure 3 with potentially have jumps in them depending on your situation.