I did not factor in captaincy because if I do that, the chances of Babar surpassing Kohli’s legacy will drop from 1% to 0%.
Kohli has not won a trophy as captain in LOIs, but he is the most successful Asian Test captain of all time with 36 wins in counting.
His team spent more time at the top of the Test rankings than any Asian team in in history and his team spent more time at the top of the rankings than any team in the 2010-2020 decade. Babar will never come close to those achievements as captain.
As far as legacy as individual player is concerned, even if Kohli retires today, he will be remembered for generations because he is easily one of the greatest in history and also one of the iconic superstars the game has ever seen.
He has defined an era and the 2010s will always be remembered as the Kohli era. No batsman has dominated all three formats the way he has.
He has also completely redefined the art of chasing in white ball cricket.
So yes, it is impossible for almost every young batsman out there to surpass his legacy including for Babar who only has 1 Test hundred outside Asia by the age of 26.
Babar at best can hope to be a poor man’s Kohli, but for that to happen, he will first need to help Pakistan chase down 300+ totals which he has not been able to do even once.
Kohli will retire with the most ODI hundreds in history, probably the second most runs in international cricket after Tendulkar, 35+ Test hundreds, most Test hundreds outside Asia by an Asian, most Test hundreds in Australia by an Asian, most ODI hundreds while chasing, most runs and hundreds in international cricket as captain. Moreover, he will probably end up with 90+ international hundreds overall.
So yes, Babar simply has no chance of surpassing his legacy. He is clearly inferior in so many ways.
He doesn’t have Kohli’s ability, mentality, aura, crease presence, personality etc. which have all combined to help Kohli become the giant that he is today.
Kohli has the same characteristics that Cristiano Ronaldo, Muhammad Ali, Tiger Woods, Michael Jordan etc. have/had in their respective fields. He is a true icon and the face of modern cricket.
His greatness cannot be captured in mere numbers. There was something about peak Kohli that no one else had. He was by far the most prized wicket in the world for a long time and he still is, in spite of not reaching his own standards in the last 2 years.
Nevertheless, Babar doesn’t have to get anywhere near Kohli to have a glittering career. You can be nothing like Kohli and still end up as a great player, because there are great players and then there greats among the greats, and Kohli belongs in the latter.
Babar can perhaps end up as the best Pakistani batsman ever, and the best Pakistani batsman ever, whoever he is today - Miandad or Inzamam or Younis - is nowhere near Kohli.