On the other hand, it allows you to write retrospective articles like this, in which you speculate about how your life may have turned out if you hadn't focused quite so much on grades.

Too bad these types of hypotheticals are wholly unrealistic. I think your standard straight A student (especially a straight A college student) would have a hard time not making straight A's. And it's really that quality (or personality flaw) that makes the grades completely irrelevant. How many C students were running a radio station and participating in the student government simultaneously?