It works, but most people generally understand it works when that big time player is the final piece to the puzzle. Not part of a rebuilding of sorts.
Exactly.............if your the Pats and all you need is a shut down corner, then go get Revis. If you are the Broncos and your team is stacked with the exception of having a great QB, then go get Manning.
If you are one player away, then signing a big ticket free agent is not a bad thing to do, its pretty smart. However, if you are trying to rebuild or put together a "dream team" then the odds of it working are slim to none.
This is not baseball, you cannot buy a championship (even though some teams have tried).