This is another wrong idea you have. New skills can be learned, especially more so today with how efficient modern training techniques are. There's nothing intrinsically limiting a Pete Sampras from adapting to a modern style provided he was young enough. By the time of that Safin video you always post, Pete was about 30, which was ancient in tennis in those days. No time to adapt at that point. This would be like saying in 2014 that Tim Duncan (let's say he retired in 2007 at 31) would be a subpar big because he was too post-reliant as the game became perimeter oriented and he was too slow-footed to step out and switch on modern pick-and-roll centric modern offense. But we saw Duncan's adaptation first hand. He lost weight. He developed his spot up jumper more. He relied more on movement within the offense to get fed than just posting up every time down. His metrics confirmed in 2014 that he was still one of the league's top 10 players.
This re ed idea is also used by Michael Jordan detractors. I do believe that the mythology of Jordan is overblown, but people think since perimeter defenders of his day weren't as long and athletic as today, Jordan would somehow be reduced to a 2nd tier all-star.
Jordan wouldn't have any problem going off on any perimeter player, from Kawhi Leonard to Doug McDermott. And knowing his pathological work ethic, he's probably one of the best 3 point shooters in the league today. It would be his and Lebron's league. Jordan would be superior to Durant, Harden, Leonard, etc.