Pretty cool article. I think you're overstating it when you say, "only 2 got to the big time." You refer to Garnett and James. I'd argue that Rick Mount, being hyped as a HSer and later being drafted #1 overall after 4 years at Purdue "made it." Also, Bruce Hardy having an 11-year career as a WR in the NFL is pretty good. Carpenter played 14 years in the NHL including becoming the first US-born player to get 50 goals in a season. Phillips made the Gymnastics HoF (seems undeserved given the rest of her write-up). These kinds of results for hyped high school
athletes seem pretty good. Also factor in the additional addition and pressure they get from this early attention.
As for Harper, you're just ignorant of baseball's contract rules if you think there's any chance Harper will play in the majors before June. I also wonder about the value of bringing him up this year instead of June '12 considering the usual career arc of a power hitter. Get him bigger, better, stronger at AAA while letting him see some real pitching for the 1st time in his life. I'm also a little ignorant of MLB contract rules, after how many MLB games does his clock start?