In the end, he drove away the people he loved, leaving only the job to keep him going. But even then, he still wanted to provide for his family first.
There's not a clear moral arc there, I don't think. You can't point to any single decision and say that was where he went wrong.
Rather, he ground away his moral fiber moment by moment, throwing good effort after bad. There were lots of tines he could have stopped and just taken a minor loss overall, but he wanted to _win_.