I forgot to add one thing (obviously, there are many other things that I could say/have said, but just focusing on this one thing right now). Regarding this 51 point game specifically, it is noteworthy that lebronze has now played in 57 more playoff games than MJ. This was lebronze's first 50 point playoff game of his career (MJ had 8 ).
Can't imagine what MJ's playoff numbers/accomplishments would look like with an additional 57 playoff games during his peak/prime years, regardless of the obvious differences in the eras.
I'd even argue that this fact (i.e. that MJ played in 57 less playoff games) has meaning in and of itself. Granted, some of MJ's earlier playoff seasons were shorter because the Bulls were eliminated in the first round, but lebronze didn't even make the playoffs his first two seasons, so I believe those are sort of canceled out in some way. I mean, who would have thought that we would be celebrating someone who consistently requires more games to get a second place finish done? For example, lebronze has played in 20+ playoff games in a year 8 times (counting this year, which will be at 20 as soon as he starts next game). On the other hand, MJ only had 2 instances where he played in 20+ playoff games in a year. (To be as fair as possible once again, I will note that the first round was only best of 5 at the time, so it is likely MJ would have had 2 other years where he was required to play 20+ games in order to get one extra win over teams that were swept in the first round... bringing his total to 4.)
Probably isn't the best way to analyze that, but the main point is that lebronze continues to get chances to add to his "legacy," and has had about 60 games more in the playoffs to date. It's not fair to fail to acknowledge that MJ would likely have had even more insane numbers if he had needed more chances.