LeBron came into the league at 18, Bird came in at 22. Not really fair to compare them by age, 31 year old LeBron has already played more career games than Larry Legend.
Not fair to compare? Wait.. What??? It's fair to compare them age 22 till now.
Bird avg over 10 RPG 6 times and avg 9.8 RPG in another. Maxing out at 11 RPG.
Lebron avg 8RPG one time. They ironically avg the exact same spg at 1.7 and Bpg at .8 over their career.
Bird obviously amuch better shooter Ft% and 3p%.
Birds better. End of story.
pace matters. Lot more shots in Bird's time (thus more opportunities for points, rebounds, assists, etc.). Bird was the better rebounder with a career RB% of 14.5, while James is at 10.8, however James is a significantly more proficient passer, Bird 24.7% while James is at 34.9% (and it wasn't a late career slide by Bird as his last 3 seasons were all well above his career average). How about TS%, Bird above 60% just twice (and above 57% just two other times), James is already above 60% 4 times with 3 other times above 57% (he is currently above 57% which would make 4). Bird scored 1.26 pps in his career, James is at 1.38 right now. The numbers are fairly similar in the playoffs as well.
Pace does matter. So do the changes in rules to favor the offense and to make the game less physical in the current era.
and yet those rule changes haven't led to more points, more shots, etc. It is definitely a different game, but it is still slower.
EDIT: Compare 85/86 to 12/13 (below are team averages)
FGA - 7268 to 6720
PPG - 110.2 to 98.1 (totals are 9038 to 8041)
FG% - 48.7 to 45.3 (even just 2PT% is 49.5 to 48.3)
RB - 3572 to 3453
AST - 2133 to 1814
So you can say the rules have changed to favor the offense, yet the offense is worse.
BTW, I chose those two years because the Celtics and Heat had almost identical regular season records, both won the championship, and Bird and James were the league MVP's.