wait ok so in canon lee cant use ninjutsu (actually idk if he physically cant or hes just really really lousy at it but lets just say he cant) so if he (or his family idk) is from ishigakure maybe its some kind of genetic thing that makes them unable to use chakra?? maybe theres a certain percentage of the land of iron’s population that have this genetic quirk and theyre the ones who developed the techniques that are the roots of most modern day taijutsu techniques, and probably someone else in a desperate attempt to unlock the chakra in their body that they couldnt access, actually opened one of the 8 gates and became the first person to have opened all 8 (and died a master of the technique as a result)

so most people can use chakra, they just. dont. why should they, taijutsu is awesome