He was supposed to become the only Super Saiyan, ever, for once in his lifetime. Before he emerged triumphant over Frieza and then get killed in the destruction of Namek.
DBZ plot went to shit afterwards when not only Future Trunks can do Super Saiyan, but Vegeta, Gohan and oh, remember that kid Goten?
O LOL LOL MY DAD NEED TO WAIT TILL HES IN MID 20S AND TRAIN IN 100X GRAVITY TO BECOME SUPER SAIYAN BUT I CAN TRANSFORM SO EASILY WHEN I AM 8 YEARS OLD AM I TEH STRONGEST! SHOULD HAVE BEEN ME KICKING THE SHIT OUT OF FRIEZA!