Hard to call it "less time" when I don't see what you expected Lebron to accomplish when he was 19-20. Jordan didn't accomplish shyt before he was 28. Take out the three years when Jordan was learning his craft under Dean Smith while Lebron was floundering on shytty teams in Cleveland, and Jordan's actually had more time. MJ floundered on shytty teams when he was young too.
But otherwise you right. Jordan is GOAT, Lebron is not. If Lebron turned in a ball of flame tomorrow, won the MVP, NBA title, and Finals MVP this year on an all-time great performance....he still probably wouldn't be GOAT. Lebron needs at least two more EXTREMELY good seasons, including postseason runs, with at least one more MVP-level season and at least another two Finals MVP-level performances, to even think about taking that crown.