I've been going down the rabbit hole, and this explains the boom in polarity with YoYos in the 90s.
There were a few ball bearing yoyos before this, but this is the first time someone manufactured and sold it as a product successfully.
SB-2 yo-yo
In 1990, Kuhn introduced the SB-2 yo-yo that had an aluminum transaxle, making it the first successful ball-bearing yo-yo