Early Dragon Ball dubbing was basically making random shit up and a lot of it makes zero sense.

Original English dub said that Bardock was a "great scientist" who invented the Fake Moon Ball Vegeta uses to transform into an ape. Which makes less than zero sense because I'm fairly certain the literal Bardock movie was already out at the time and available to prove he was a meathead warrior.

No information we had available through the entire run of DBZ showed that Saiyans were capable of or had anything but warriors, afaik. It wasn't until Dragon Ball Minus (a literal piece of shit Toriyama cranked out to steal Bardock for himself) that we saw it was even possible to not be a mercenary or warrior on their planet.

It wasn't until like mid-Freiza that they started to get somewhat close to the original text in a general sense. Which is also when Vegeta, a guy who would know better than anyone, started saying "a warrior race" constantly and never mentioned a single other type of Saiyan (until his brother in a special not everyone Toriyama cared to reference).

I think the original Broly movie showed the most likely scenario. That they would enslave other weaker races to do all the work for them.