I experienced this when growing up in a big Glasgow housing scheme in the sixties. Our school team had an abundance of talented young boys but there was two in particular who went on to play professional football, one at the top level. These two were dedicated and had the right attitude. The others were just as talented but lacked the desire , attitude and commitment to make a career out of football. By the way the one who played at a high level was the grandson of Willie Salisbury who played for the jags team who beat Rangers in the 1921 Scottish cup final.