If you thought about it a little bit you will find that the sayans got no upper hand on frieza like in terms of potential it took goku and vegeta years to achieve super sayan blue just to be surpassed by frieza in couple of months imagine how much more powerful this monster got after 10 years of training in the manga he managed to one shot both tui goku ue vegeta at the same time
(English is my second language so I'm sorry if there is a mistake)
