I was worried about bricking mine at first. Once I was comfortable with how to do it, those fears went away. If more people were aware of the advantages of rooting/jailbreaking, I’m sure more people would be doing it. With my iPhone, I started hearing some people I know talking about it and I asked them what it was. When they first told me, I didn’t really see the point of it. As time passed, they started showing me things that their phone was capable of and mine wasn’t (namely tethering among others). Apple tries to stifle the jailbreaking with nearly every update they push, but the jailbreak devs always find a way around it. Android manufacturers started locking down bootloaders...HTC to be the latest one, but after the huge outcry, they changed their minds.
If more people knew about the advantages of putting a custom ECU mapping in their car, mo--, no, just about the same number of people as now would be doing it. It's a gearhead thing, not a regular driver thing.
Try explaining “rooting” to somebody who thinks “rootkit” comes in a box that says “Clairol”.