Give me 5 examples of a starting QB on a contract like Kyler has being traded and what they got. You can't because it rarely happens. Darnold was traded after 3 seasons, the third of which was the worst of his 3 years. They literally traded him to make room for Zach Wilson, that's how little the Jets thought of him, and they still got a 3rd.
If Murray doesn't completely meltdown the rest of this year the Cards will be able to trade him but how he does the rest of the year will determine what we get in exchange. Acting like anybody knows in early october what that value is, is just wrong. Nobody knows.