This is debatable. A lot of his losses were a function of the fact that he was not a full time professional fighter. When he was a full time professional fighter, he was really only losing to the same men as Ezzard Charles.
If you compare their records, you will see that Cooney never beat anybody ranked in the top ten, while Walcott was the undisputed heavyweight champion. The records are really not Cooney's friend here!
And yet out in the woods of Germany hunting with his dogs stood 76 year old Max Schmeling. Far too live and majestic for consideration.