Expecting someone at a selection to be worth exactly that is more of a problem.
Just because someone is picked at a selection, does not mean they're worth that selection. Kids are selected ahead or after where they should be talent wise based on needs, locality, position and so many different reasons. Neither is the pick someone is traded for later in their career an accurate measure of their talent when drafted. The two aren't particularly correlated.
You could pick someone high based on their talent but if they don't have the work ethic, the support at the club and the right system to develop them, they aren't going to amount to much. Similarly, someone with less talent could be picked up late but work hard, have a great support network, coaches building systems around them and excel in their development.
Earlier draft picks give you access to the best talent and if your talent ID is as good as ours has been the past 5 years, you can make great use of it. There's a very high rate of good talent prediction on draft day but that's only part of the equation.