LeBron James has been to 6 consecutive NBA Finals. That is a streak that has only been matched by his teammate James Jones since the Celtics finished up winning 8 straight titles in 1966. While the streak is undeniably impressive, there are a few factors that have allowed him to sustain this period of dominance.
First, while he has not always been the MVP during this reign, LeBron has been the league's best player. Second, LeBron has had some great players on his team, from Dwyane Wade and Chris Bosh during his time in Miami to Kyrie Irving and Kevin Love on Cleveland. But perhaps the most important factor has been the fact that LeBron has been playing in the Eastern Conference. During this six-year stretch, the Eastern Conference has had very few teams matching the quality of the West and has had very little depth of really good teams.
The best Eastern Conference that LeBron has faced was in 2011, during his first year in Miami. The Chicago Bulls held the best record in the NBA, followed by the Spurs and the Heat. This is the only year during this streak in which 2 of the top 3 teams in the NBA have played in the Eastern Conference. The top 4 seeds in each conference were fairly evenly matched, with the Orlando Magic (the Eastern four-seed) record being 3 games behind the Oklahoma City Thunder (the Western 4-seed). However, the depth of the West was much greater than that of the East. Despite the even split of the top 8 teams, 8 of the top 12 teams in the NBA played in the West.
LeBron's second year in Miami provided a similarly strong, though slightly weaker up top, Eastern Conference. In 2012, the East and West were probably as even as they have been throughout the streak. However, after leading the Chicago Bulls to the best record in the NBA, Derrick Rose tore his ACL during the first round of the playoffs. After Rose went down, the 1-seed Chicago Bulls fell to the 8-seed Philadelphia 76ers, clearing an easier path to the finals for Miami.
During Lebron's third year in Miami, the Heat had the best record in the NBA at 66-16. That year 6 teams in the NBA won 55 or more games with 5 of those 6 teams playing in the Western Conference. The only other team in the East to win more than 50 games was (somehow) the New York Knicks. That may be the clearest sign of a truly pathetic conference.
LeBron's final year in Miami provided the larger disparity between the two conferences. The top three records in the NBA belonged to the Spurs, Thunder, and Clippers, all in the Western Conference. The Pacers had the fourth best record and the Heat tied with the Pacers and Rockets for the fifth best record. Those two teams were just all the Eastern Conference had to offer. 8 of the top 10 teams that year were in the Western Conference. That means the 8-seed in the West had a better record than the 3-seed in the East. The Spurs first-round matchup would have a better record than any team the Heat would have to play until the Eastern Conference Finals.
LeBron's first year back in Cleveland saw a slight increase in parity, but just barely. 6 of the top 8 teams and 7 of the teams to win 50 or more games played in the Western Conference. While the Atlanta Hawks held the second best record in the NBA, they were without their best defensive player (and only hope at stopping LeBron), Thabo Sefolosha, after his leg was unjustly broken by a police offer (a case he later settled $4 million) during the playoffs. The Cavs went on to sweep the Hawks, which they very well may have done even with Sefolosha, but having the Hawks having their defensive stopper certainly would have helped.
During LeBron's most recent trek through the East, the conference provided the most depth it had during this 6-year stretch. 8 of the top 12 teams in the NBA played in the Eastern conference. However, that depth is very bottom heavy. The top 2 teams in the NBA, the Spurs and Warriors, played in the Western Conference. The Warriors held the best regular season record in NBA history at 73-9, while the Spurs tied for the 8th best regular season record at 67-15. The third and fourth best records belonged to the Cavaliers and Raptors, both in the East. The fifth and sixth best records belonged to the Thunder and Clippers, both in the West. So despite 8 of the top 12 teams being from the Eastern Conference, 4 of the top 6 still played in the West.
LeBron's streak of 6 consecutive NBA finals is truly amazing but he has certainly had his fair share of help along the way.