Why did F1 drivers rarely join the shifter karting championships in the past, such as super ICC (now KZ1)
I noticed that most F1 drivers debut before the early 2010s join in Formula A or Formula super A (now KF class) and then graduated to junior formula racing. Drivers like Vettel even graduated to Formula BMW directly after winning the J-ICA (now OKJ class)championships
For example, before joining Formula Renault, Jules Bianchi mainly participated in Formula A championships and a few ICC races.
After Trulli and before Verstappen, there was no formula C(or ICC,super ICC) winner of the Karting World Championship finally become a F1 driver
