I may be well off with this theory but maybe it has something to do with the fact that so early on in his career he inherited a dominant Red Bull that more often than not sped off way into the distance and won at a canter. Such cars never allowed him to truly race wheel to wheel with the very best at a critical age when he was rounding and moulding his ultimate driving capabilities.
Lewis has always had excellent race craft such is his nature but while he had handy McLaren's to drive in the first part of his career they were never so good or as dominant as the Red Bull's Vettel drove during the same era so he found himself defending and fighting wheel to wheel more often than his German rival at the same stage of his career.
Maybe. Although I think when it comes down to ruthlessness that Hamilton, much like Alonso, is a level above most of the grid.
Vettel more emotional than them, which can be seen in the aftermath of the race yesterday.
Like you said though, Hamilton has learned the hard way from his mistakes early in his career.
Mistakes that cost him a title in his debut season, when he had to battle against Alonso and Kimi.
Don't think Vettel ever ironed that out. Going to Ferrari can only add to the emotional aspect.
Mercedes would only increase the methodical level that Hamilton operates at.