Trading baseball players for anything of value is impossibly hard.
A GM only has 29 potential trade partners, and of those he must find one that's usually in the exact opposite side of his team's location in the standings. There's a desire to win the trade, of course, but there's also the desire to maintain amicable enough relations with the other GM so that there's not irreparable damage done to the relationship that would prevent advantageous trades in the future. There are infinite rolls of the dice, and there's a non-stop juggling of scouting information (much of which gives completely conflicting opinions on individual players).