So a decorated and good QB in Matt Ryan is traded for a 3rd round draft pick? Why? His salary and cap cost is so high.

Same reason Woods was traded for a 6th. A WR isn't even in the same Universe in value as a QB. Woods held a substantial cap number and the Rams needed to dump cap.

Cap costs have to be factored into trades. It's one of the reasons the Rams gave up a 2nd and 3rd for Miller; the Broncos were willing to eat almost all of his salary and therefore of cap cost.

It's just how it is.