By mathematical necessity, teams that draft 40 players each year to replenish 25-man rosters whose occupants spend an average of 5.6 years in MLB will "miss" on at least 88% of their draft picks.
So although it's easy to point out the misses, it's not convincing.
The goal of scouting isn't to convert as many early round picks as possible into MLB players.
The goal is to sign the talent that can be developed to enable the parent team to win. Maybe some of those late rounders who make it are actually triumphs of scouts who looked past the measurables, saw potential, and knew the market would allow them to acquire talent at bargain prices.
Even in an age when everyone has the same objective information, or maybe especially in such an age, the subjective opinions of competent scouts can give their teams an edge. And since MLB is a game of small differences over the long haul, that edge can prove significant.
But differences of opinion are what make horse races, markets, and discussion boards possible.
Best wishes,