The dilemma the Angels face with Trout is that any package "worth" Trout would gut the other team's talent pool so dramatically they would be in the same boat the Angels are currently in...Trout and not much else. A package for Trout would represent an unprecedented amount of talent going both ways, and is unlikely to happen. The only 2 teams that could possibly pull off a deal like that would be the Cubs or BoSox.
This type of trade is not your typical "send equal WAR/$$ value by bundling good players together until they reach 10 WAR". There would have to be so many players sent to the Angels that WAR consolidation and physical number of positions on the roster become real problems. For example, on paper, the BoSox could send over 4 guys that project to produce 3+ WAR over the next 4-6 years, and that would seem to be "fair" for Trout. The reality (and problem) is that those 4 guys aren't replacing just Trout, they are replacing Trout plus 3 other guys on the roster who are (or will be) likely worth a combined 4-6 WAR, so the net improvement for the Angels is actually negative when you replace 14-16 WAR (Trout plus 3 current Angels players) with only 12+ WAR from the 4 guys you got.
So the other team would have to include even MORE. So something like 6+ guys that project to produce 3+ WAR for 4-6 years. Suddenly, there are no teams that can even produce that amount of talent, and if they did, they would be just as crappy as the Angels are now.