The Combine is a great way to measure things like pure speed and strength. Maybe some fans take it as gospel, but the fans aren't the ones making the picks. Of course success in the combine doesn't translate to success on the field, that is why scouts use it in addition to game tape, player/coach interviews, and many other tools. Just like anything else in football, nothing is guaranteed. It's as simple as this: if you were a GM, would you rather know a potential player's 40 time and bench press or not?