The stats prove Lebron isn't capable of good efficiency at high shot volume
We didn't need the 2015 playoffs to prove this - the NBA's player-tracking stats show that Lebron is bad at the additional midrange and isolations required of high volume shooters.. Lebron's poor efficiency at high volume dooms his chances of winning a CHAMPIONSHIP while shooting high volume - he simply isn't capable of winning a ring while high shooting volume.
Lebron's poor efficiency at high volumes mean he doesn't require a double-team
He hasn't been double-teamed for the last 3 Finals, most obviously in 2015.. This is no surprise - the best option for ANY defense is to allow low percentage shots over and over.. This specific dynamic where Lebron UN-complicates the opponent's defensive strategy
by not commanding a double-team, puts him outside of the top 15 all-time.. His inability to command a double team is a horrible indictment on his game compared to his peers.
39% is Lebron's best capability at high shot volume
The lack of double-teaming in the 2015 Finals provided Lebron with optimal conditions
to shoot the best percentage possible at the higher volume - this turned out to be 39%.. 39% is Lebron's ceiling at higher shot volume.. Again, this would never be good enough to win a championship - when MJ averaged 41/9/6/51% in 1993, it was BARELY enough for the Bulls to win because remarkably, both teams averaged exactly 106.7 ppg and 113.0 ORtg in those Finals.
Lebron's poor mid-range and isolation ability prevents him from being as good in the 80's, when those were the only options left in the absence of the 3-pointers necessary to make screen-roll/drive-and-kick mathematically worthwhile.
Without teammates spreading the floor for him and making drive-and-kick the force it is today, Lebron would have to score from the mid-range like everyone else in the 80's - since he sucks at mid-range, we know for a fact he would be a lesser player back then.
However, Lebron being worse in the 80's without drive-and-kick isn't the only impact of Lebron's poor mid-range ability.. It's already been mentioned how Lebron's lack of mid-range ability also makes him incapable of having good efficiency at higher shot volumes, since additional mid-range is required of high volume shooters - of course, Lebron's inability to shoot well at high volumes means he doesn't require double-teaming, which uncomplicates the opponent's defense and makes him highly exploitable.
Faster pace wouldn't help Lebron in the 80's because the stats show that pace ALWAYS slows down in the playoffs, regardless of era
Pace was 94.0 in both the 1988 and 1989 playoffs, which is lower than the 2015 playoffs (94.4).. Playoff pace was often MUCH lower, like in the mid-90's - i.e. pace was 87.4 in the 1996 playoffs.
Lebron's style of play dooms his team's chances against the better playoff teams, resulting in "empty stats"
Lebron's style of play (pg ball-dominance and low-assisted rate from SF position, with poor mid-range or isolation skills) doesn't just prevent him from being effective without drive-and-kick or shooting well enough at high volumes to command double teams - it also hurts the brand of basketball his team is capable of.. His teams become locked into a style where Lebron dominates the ball and the offensive decision-making, which hurts chemistry.
Just look at the heat.. Wade and bosh's stats were much lower and chemistry was always an issue - Wade and lebron's ON-OFF stats were well-publicized and showed the heat were better when they were not on the floor together.. They still went 2/4 due to talent, but the times they lost, their chemistry and brand of basketball was far worse than their opponent (dallas, spurs).. The lesser brand of basketball falls primarily on Lebron's shoulders - as the franchise player, he's most responsible for the brand of basketball his teams are capable of.
Ray allen's walk-off in 2013 merely postponed a trend where opposing teams play a superior brand of basketball and render lebron's stats empty - they're empty whether he takes a passive 17 fga on all 3-and-D to protect efficiency (2014 Finals), or whether he doubles the fga to 34, but the additional isolations and midrange required of high volume shooting tanks his efficiency (2015 Finals).