It is a datapoint. But it is evidence of what folks observe in college, high school, minor league baseball. Players who are competitive (not great, just competitive) at very young ages are excellent bets to have good careers, and also where your extra-special careers come from. I wish Bogaerts were more like a 4-win player than a "somewhat above replacement level" - that would make the projection much much more confident. But he was a competitive big leaguer - better than 2006 Pedroia, better than 2012 Iglesias. When you are his age and able to belong in the big leagues in any reasonable capacity, that is a VERY strong harbinger for a long career playing baseball for a living, with good odds of being a hell of a lot more.
For Fred, the 2013 Cardinals made the world series with .330/.402/.463 with RISP. This year, with very similar human beings it was .254/.336/.365. Did those players become dumb or stupid, or have what happened to those dudes in the beginning of "Space Jam"?