What if Frieza never destroyed the sayains?

Kakarot vs Broly

One day, Kakarot was training, when he decided to take a ship, and patrol the surrounding space area. He looked around over and over again. Nothing. He decided to go back to training, he had almost mastered how to go in and out of his new form, Mastered Ultra Instinct, he had followed the instructions from King Vegeta, according to sayain legend. He had seen nothing out in space, but he felt a strong presence, it was a very faint feeling, but he felt it nonetheless. He had decided to not pay attention and train until he got it right. He cleared his mind, thought about nothing, and charged his ki, he felt a surge of power and started moving around at blinding speed. All of a sudden a man came around. He marvelled at this state and asked what it was, Kakarot explained his new form, the man was shocked. He asked if he could spar with Kakarot, and since Kakarot was always looking for a challenge, he accepted, especially because he could sense this mans power level to be just as big as his. They went to the battle arena, and the man properly introduced himself, he said his name was Broly. Kakarot introduced himself as well. Kakarot charged at Broly and punched him in the face, he looked as though he hadn't felt anything, Kakarot had used Kaio-Ken and punched him again. He just stood there. Kakarot stepped it up and used Super Sayain Blue Kaio-Ken x5 and hit him, Broly went flying. Kakarot charged him and used a Kamehameha beam, he aimed at his head specifically. He hit him, he was sure that Broly had been beaten, but when the Kamehameha died down, he didn't see Broly. Broly was behind him, he had punched Kakarot, he went flying across the planet, he went all the way around until he came back behind Broly. Broly had been in a weird state, his hair was green and all spiky, instead of his usual black, long hair that he had before. Kakarot asked what this was, Broly had explained, he was the Legendary Super Sayain, a special power bestowed upon one sayain every thousand years, it is said to have an endless energy supply. Kakarot realised he had to step it up, he turned into his new form, Mastered Ultra Intsinct, combined with Kaio-Ken x100, he fired a Kamehameha wave and pushed him back, he then flew forward and uppercutting him in the jaw. Broly fell to the ground, Kakarot punched him in the face. It seemed like it was all over, he had killed the Legendary Super Sayain.