A $50 subscription to Baseball America will tell you all about the prospects that everyone knows about. No scouting directors hire scouts that are just going to follow the guys that everybody else is following. What seperates the elite organizations is finding gems later in the draft or finding lower profile international free agents who have some projection and who can develop into big leaugers. Some will cause those types of "finds" just dumb luck...I would call it some scout somewhere saw that kid play, liked what he saw, and then had the cojones to go to bat for the kid because he thought the kid could play.
A lot of times it's also going to mean that someone like Coach May saw a kid play very early and saw that he was someone to keep an eye on. Then that scout followed that kid and saw him play as often as possible and that scout knows that the kid may not be hyped but he can play. Again, that scout has to have the stones to say "I think the other scouts are wrong". Scouts are hired and/or fired based on the players they recommend. A scout who only recommends the players everyone else knows about is not going to be employed for long. Why? Because why would I pay a scout if I can just subscribe to BA and get the info I need?
The thought that scouts don't make the extra effort to find players is absurd. Finding those players is their only job security (I believe most scouts still work on year to year contracts, so if you don't find players, you are not retained). What's more likely is that the folks who make these complaints really have no idea what it takes to play at the MLB or MiLB level. That is my opinion at least.