The sage said he was a late bloomer.
Biased ass mf.
Its because he used s jutsu bracelet.
Bijuu,senjutsu etc still require training ,self control,power and provide a life or death risk.
If Naruto messed up his sage training he would be dead. Same with taming kurama, he had to divert from the path of hate being kuramas jinchuriki,this same hate would've made kurama kill him,who else could forgive konaha like that. Naruto confronted his own demons as well as fought to save tailed beasts he earned thrm cause he was risking his life.Son Goku saw Naruto truly wanted to help and rewarded him cause he was one of a kind. Naruto and Sasuke differ in that Naruto has more self control. The village that pampered and loved sasuke he ended up hating. The village that tortured Naruto he grew to love and forgive.
All the adverse conditions presented by bijuu and senjutsu related power far exceed that of a jutsu bracelet.