Only in the imposed system of judgement of academics, not your own pursuits.
Many people with poor school histories succeed fantastically when working on their own projects and passions.
Fairly successful guy here. No they don't. I worked till 5am last night on a new business. I absolutely hated school. I love to learn. We all learn differently but the system works for one type of learner. When I dropped out of high school I took the GED, of the guys I took the test with, most of them scored in the 90th percentile. We were all smart, and most of us liked to work, we just didn't fit the system.
Do they? Good grades indicate grit in getting good grades. The question is whether that translates to other areas of life.
No they don't. That's the lie the corporate world wants consumers to believe.