Some dogs are highly intelligent and readily trained and some dogs aren't. You can guess by looking at their phenotype, i.e. breed, although not every dog of a preferred phenotype is capable.
Someone may be gifted at dancing. Someone may be gifted at singing. Someone may be gifted at hunting.
Why do we insist academic pursuits are equally available to everyone if we only throw enough resources at them?
Any selective program, music, athletics, military has a minimum entry level they're willing to accept. They know you can't turn a random person into an elite musician, athlete, or soldier.
Why does academia have to pretend that academic talent is evenly and randomly dispersed?