I honestly think Lebron will be the last person to have a realistic shot at catching Malone, let alone Kareem. Even if another genetic freak comes along, having a prime of 20 ish years where the guy plays 75+ games every single season has to be considered so minuscule that I just can't see it happening again. Even if that guy remains relatively healthy with load management, rest, etc. I just don't think a true legit scorer like that will get the requisite games played. I mean look at someone like Carmelo. He has just over 26,000 points. He is still nearly 11000 points from Malone and you are talking about one of the greatest scorers of his generation. Durant has 23000, Harden has just over 20,000. Last year Harden had 2800 points playing in 78 games. To even catch Malone he would need nearly 6 more seasons exactly like that (and that isn't happening). Though I suppose if Harden plays till he is 40 he might catch Malone.
Even if they don't shorten the season, I just don't see anyone else really getting the games played at the level of play needed to get there. Then again genetic freaks come along every so often, so who knows maybe someone gets there some day. Though I do think Lebron is going to blow way past Kareem so getting to him may be impossible, but maybe someone else catches Kareem.