"Because they just don't do their homework," Novak Djokovic's former Australian strategist Craig O'Shannessy told AAP at Melbourne Park.
The top-ranked Alcaraz and two-time defending Open champion Sinner have gobbled up the spoils at the past eight majors stretching back to Djokovic's 2023 US Open triumph.
And O'Shannessy believes the pair of grand slam gluttons will continue cleaning up until their rivals start studying up more on any shortcomings, however small they may be, that Alcaraz and Sinner possess.
"It's the only chance they have," he said, explaining how the top two have taken their own tennis to extraordinary new levels to leave their pursuers miles behind.
"As soon as he lost last year's Wimbledon final to Sinner, Carlos Alcaraz came straight off the court and instantly realised he needed to update his game on how to beat Sinner.
"So he got with his team, they studied that match and then they created drills for the practice court on how to improve.
"The strategy was specifically about playing one player and one player only - Sinner.
"They implemented that game plan, broke down his game and knew what he was doing in infinite detail, and they created a counter for that style.
"And then of course Sinner did the same thing when he lost to Alcaraz at last year's US Open."
O'Shannessy, who helped Djokovic emerge from his mid-career funk and capture four grand slam crowns in 2018-19, hailed Alcaraz and Sinner as tennis versions of fellow sporting greats Kobe Bryant and Tom Brady.
"The best athlete that did this kind of opponent analysis was Kobe Bryant," said the Texas-based coach and analyst.
"He studied the movement of the player, the footwork of the player. He studied their body language.
"He studied how teammates interacted with each other and he knew more about the opponent than they did.
"And it was also exactly the same as Tom Brady, who famously studied opponents and came out and said, 'I know their defence and I know their players better than they do' and found their vulnerabilities.
"Sinner and Alcaraz are rewriting the book of Kobe Bryant and Tom Brady."
O'Shannessy suspects why rivals of the rampant top two aren't doing the same type of homework.
"Because they're too much about themselves," he said.
"They need to understand that you are the second-most important person on the court. Your opponent is always the most important player.
"So the number one question in tennis is: Is it more important to hit the ball where you want to hit it? Or more important to hit it where your opponent doesn't want it hit?
"Like, ding ding ding.
"The rest of the field are just second-week fodder if they don't wake up.Â
"Find the opponent's weakness and hammer it."
In a rarity, nine of the men's top 10 players have made the last 16 in Melbourne.
O'Shannessy, though, predicts the second week will showcase more of the Alcaraz-Sinner dominance unless their rivals take a leaf out of Eliot Spizzirri's playbook.
O'Shannessy - who knows Sinner's game better than most having helped mastermind the renaissance in Italian tennis after working with the country's federation for a decade - liked how Spizzirri made life difficult for the world No.2 on Saturday.
"You have to attack Sinner," he said after the second seed escaped with a four-set fourth-round win over the American.
"Sinner loves the ball at his hips. He loves the ball hard and he plays like a ball machine.
"Spizzirri used shape and spin to get the ball out of Sinner's wheelhouse.
"He mixed it up and Sinner didn't like that."
