Not always and like all other aspects of player acquisition, it has to be done correctly. You think the Patriots made a mistake going after Josh Gordon? Nope! Did the Cowboys make a mistake giving up their 1st round pick for Amari Cooper? Probably. Perfect example to support you theory in Dallas, but debunk it in New England.
There is nothing wrong with a trade for a player who can contribute for 3-4 years. That's about the life you'll get out of most players, even rookies unless they are good and then you're guaranteed 5 years. But if you can pick up a player of Patrick Peterson's ability for 2-3 years of service for a 3rd,4th,or 5th round player, or maybe even 2 later round players if there are performance clauses built in, then those types of moves are ok.
That's part of the problem with this front office, you cannot build a champion through the draft alone, adding only 3rd and 4th tier free agents like Paul Richardson. If you want to be better than the year before at a position of need, a 4th tier guy is not the only asnwer, bring him in WITH Allen Robinson. Make an offer for Josh Gordon that won't kill the future.