This was definitely a thing just back in the 2000s. You had guys like melo, tmac, Paul pierce, wade, Dwight ect all decline in this age range or way before. People always mentioned lebron still being so good when he was 33. At first that seemed like an anomaly. Now, you have guys like curry, kd, kawhi, dame, lebron still(lol) jimmy butler, all still being in their prime at 33+. Is it an advancement in technology and medicine? Something else?
This about sums it up
It’s definitely a factor, but we also have to accept that some players will be outliers. I think this argument would hold better if there were a ton of role players also playing well enough to keep jobs over young up and comers.