With less talented players back then as well.
To some degree.
Put Westbrook talent in the 70s or Dr J in the 2010s you'd see a better Dr J and a worse Westbrook. But their talent is the same.
Nutrition, year round training, conditioning, strength, nutrition are night and day
Barkley tells stories of the when he joined the Sixers and the eating habits of Mo Cheeks, Dr J and Moses Malone were terrible and the offseason work was "go fishing"