Because it had been so long since the stories of an actual super saiyan existing had occured, it was declared that broly, a young saiyan baby had been born a super saiyan, and while he was different from every other saiyan from the past and every super saiyan to come later on in the future, he himself was not the true Legendary Super Saiyan. As time passed, multiple saiyans ascended into their super states, which came from obvious training, unlike the previous saiyans who spent too much time warring with other planets and pirateering.