This view is useful, but seriously clouds the value of a stud athlete if he makes it to the major leagues. First, because these career WAR totals reflect both higher per-year WAR accumulation, and longer careers. Second, because you can't put together a winning team by promoting 50 1.0-WAR players to the majors in a season. The constraint of a 25-man roster looms huge, in making grade-60 prospects more valuable than 55-grade. I was being a little flippant in suggesting an actual exponential weighting (and I backed off of it in the next breath). But it's far, far from linear.