LeBron led his team all the way to the NBA Finals and failed to lead that same team to one Finals win, not one, while shooting 36% from the field and 20% from the three point range (4-for-20). That Finals series included game 4 where the Cavaliers lost to the Spurs by 1 point and LeBron missed 4 free throws. LeBron averaged 5.8 turnovers in those 2007 NBA Finals.
In LeBron's first two games against the highly touted Boston Celtics in the Eastern Conference semifinal playoff series last season, LeBron shot a whopping 19% (only up from 11% from game 1 because he shot lights out for 25% from the field in game 2) from the field and committed 17 turnovers.
In the pivotal game 5 at Boston, the Cavs had a 14 point lead late in the second quarter against the Celtics. In that game 5, from the time the Cavaliers were up 14 points, 43-29, with 3:49 left in the second quarter until the end of the third quarter, where the Celtics led 72-63, LeBron played all 15:49 minutes and went 1-for-6 from the field, including 1 shot blocked, had 2 points and 1 assist, committed 1 turnover and 1 foul, shot no free throws, and pulled down no rebounds. So, on that 43-20 run by the Celtics, LeBron's leadership was on full display. This was just last season by the way, a few months ago.
I've already said in this very thread that LeBron is now the better player. He has more talent and more natural ability. But, if someone is arguing that Kobe is the better player--and it's still very much a debatable topic--it's not only free throw shooting that gives Kobe the edge. LeBron is better, but you cannot argue that he has more mental toughness or more of a killer instinct than Kobe. That's a failing argument.