You say that Wentz is better, has a stronger arm, etc., than JG. Based on what evidence?
Since when have strong arms been the key to QB success? Brains, reading D's, and leadership qualities play vital roles for a QB.
I don't claim to know why Wentz has fallen from favor. But, clearly, the NFL (and the Rams) think more of JG than Wentz, and they had Wentz for several months.
So, rather than snipe at their choice with near zero inside knowledge, perhaps we ought to ask what exactly it was about JG that they preferred over Wentz.
And, of course, money plays a role as it does with every play acquisition.
