Like RS said, it’s all relative. These “greatest athletes” or “toughest sport” discussions usually go no where because you are always comparing apples with oranges.
NBA basketball players are incredible athletes, but are they the best in the world? No, they are the best at what they do: PLAY BASKETBALL. Sure some of them are strong and explosive but compared to olympic weightlifters and track and field throwers they pale by comparison (for example the 1992 Olympic champ in the shot put, Mike Stulce, had a POWER clean of 510 lbs).
Sure they are fast but not as fast as Olympic sprinters, and again not as fast as some weightlifters and throwers (that outweigh them by 50-100 lbs.) over short distances. Another example of this would former BFS posterboy Stefan Fernholm (discus thrower) who ran a 4.25 40 yard dash at 275 lbs.
Many of them have outstanding jumping ability (which you would expect considering practice is one big plyometric session), but the vertical jump numbers you see are usually inflated (i.e. estimated vertical based on a dunk in a game, one step vertical jumps, running start, and just flat out exaggeration). While some (Vince Carter comes to mind) have unbelievable jumping ability, most would again pale in comparison to the jumps done by weighlifters and throwers at much higher bodyweights. Again as an example Stefan Fernholm was reported to have a 40" Vertical at 275 lbs.
Sure basketball players have great agility and body control but would have to pale in comparison to a gymnast.
They also have to have a certain level of endurance, but the true champions in that area are your Ironman Triathletes and Ultra Distance runners.
So again I’d say that NBA players are great athletes, and many could do well in other sports if they trained for it, but they are not the “Worlds Greatest Athletes” they are only the world greatest basketball players.
p.s. If you can’t tell I tend to refer a lot to weightlifters and track and field throwers because that is what my athletic background was in.