How Good is Rocky Marciano’s Resume Actually?

Johnson won the title from a man in his prime,a man younger than himself,only 1 of his challengers was older,Jeffries.
Marciano took the title from a 38 years old man,defended against him and 2 other men who were older than himself,his only young challengers were fat Don Cockell,who had no business being in there with him,and the protected Lastarza.
Johnson's reign was certainly not distinguished,but his circumstances were radically different to those that Marciano found himself in.Quite why Johnson and Louis' title reigns are under scrutiny is baffling,[well not Johnson's lol ,] the subject is after all Marciano.