I heard AI (Allen Iverson for the younger folk that don't remember him) says this the other day on his podcast and I would agree with it.
I think Jordan is the greatest because of the competitor he was. He just oozed greatness at a different level than Lebron. Jordan was an athletic freak, but James is a point guard in a power forward's body with the strength of a 5 and the speed, agility and jumping ability of wing - his gifts are seemingly unmatched - maybe only matched by Wilt Chamberlain. To your point it is hard to compare different eras, but peak Jordan is the GOAT. Jordan would have probably scored a lot more in today's era and he probably would have changed his game some, but he was the ultimate competitor.
I am less than 40 by the way and have watched both of them play quite a bit.