Why would the U.S. "renegotiate" such an agreement? It was subject to renegotiation, then why the hell was it signed in the first place?
It took decades for us to recover Europe after WWII and it served us to do so for just as many decades.
If the U.S. allowed Germany to elect a Nazi government in 1946, Harry Truman and everyone in his administration would have been chained to flaming barges in the Potomac River.
As to your second point, I don't disagree. That was a mistake resulting from the PC side of GW Bush and his religion of peace philosophy.