There is no doubt that LeBron has to be mentioned in the conversation. The greats make others around them better and he in-truth does just that.
I believe that LeBron makes role players better but does not make star players better.
He does a terrific job of drawing help defenders and finding open shooters & rim runners for high percentage shots which greatly improves limited offensive threats.
However, I believe he is too ball-dominant - too much dribbling around the top of the key - to get the most out of his more talented teammates. Guys who can create on their own. LeBron domineers an offense. He holds the ball too much. Dribbling, surveying instead of moving the ball. In doing so, LeBron stops ball movement and team passing in favour of his own playmaking. Therefore limiting how much his teammates get to touch the ball and make plays on their own. Which still works for LeBron because he is so darn talented and efficient at what he does.
When placed alongside other perimeter guys who need a lot of time on the ball as a ball-handler, I believe LeBron makes those guys worse (Wade, Kyrie). They do not have enough opportunities to truly exhibit their talents.
When placed alongside big men, LeBron rarely lets them facilitate from the high post. He gives them low amounts of touches. He does get them some great looks around the basket and he will let them go one-on-one in a post-up but they are not involved (involved enough) in the game as passers (Love, Bosh, AD). They are side-pieces. Guys who must play off of LeBron rather than LeBron playing off of them (at times) and allowing them more room to display their gifts.
For all the negativity about Kobe Bryant, he had great on-court relationships with Shaq and Pau Gasol. He gave them room to be team passers, playmakers, individual shot-creators and finishers in team offense. All around offensive threats. That is something that LeBron is still struggling to do now with Anthony Davis (the most talented big man in the league today IMO).
There is little give and take with LeBron. Just take.
That works great with limited offensive threats (role players - spot up shooters, rim runners) but not so good with talented stars who need more opportunities on the ball.