Durant earned 20 of 30 first-place votes in a poll featuring executives, coaches, scouts and former players conducted by Fred Katz, Ben Standig and David Aldridge of The Athletic.
Beal is the league's top scorer at the All-Star break with an average of 32.9 points per game, while Joel Embiid is the only other player with a scoring average over 30 this season. But voters still see Durant as the toughest to guard.
"K.D. is either going to make or miss shots and you will have nothing to do with it," one general manager said. "He gets to the shot he wants with length [7'5" wingspan] that is absurd."
Durant has been in and out of the lineup this season and was out all of 2019-20 while recovering from a ruptured Achilles, but in 19 games this year, he is averaging 29.0 points per game while making 43.4 percent of his threes.
The four-time scoring champion played alongside big-time scorers for three years in Golden State with Curry and Klay Thompson and is doing so once again in Brooklyn with Harden and Kyrie Irving to great effect.
Harden, meanwhile, got four first-place votes, while Irving received one.
"[He's] unguardable with his ability to handle, pass and shoot," a scout said of Harden. "Incredible footwork and I.Q. You just hope you catch him on an off night where he's not into it."
Curry rounds out the top three while averaging 29.7 points per game with a 41.1 three-point percentage, which is actually down from his career mark of 43.3 percent.