Was it an abundance of wisdom that allowed one such as Job, a rare opportunity to retire a tremendous karmic burden in a relatively short period of time?

This is, as well, an astute observation. Most people would not achieve success faced with the level of karmic negativity he had to cope with. Most would have succumbed to interminable suffering and ended their lives in that state of being. It was the fact he was strong to begin with that enabled him to endure and transcend these troubles by persevering under the most difficult of circumstances. That was due both to his character as well as the wisdom he had accrued from his upbringing.