The oldest player to ever have played in an NBA was Nat Hickey, who played one game in the 1947โ48 season when he was 45 years and 363 days old. He decided to activate himself and played in a game for the Providence Steamrollers where he missed all six of his shot attempts and only scored two points from three free throw attempts. He only played in one more game before retiring as a player two days shy of his 46th birthday.
Does Lebron play long enough to beat this record, or even as a 46 year old player in the league? Well, to do that he needs to play until the 2030-2031 season, which if it happens, will be his 27th season in the NBA. At this point, he's already just 1 season shy of Vince Carter's 22 season record, so 27 seasons seems ridiculous. But considering the shape he's in and the value he still adds to the Lakers, I'm inclined to never say never.
I am 100% sure someone would sign 46 year old lebron to play 10 min off the bench on skill alone if he kept himself in shape, when he stops playing it'll be due to him wanting to stop or injury instead of declining.
So the question is probably more about whether he would instead of whether he could.