It’s a phone, a consumer device. Anything more than “press this button to update your phone” is geeky. I’m a geek, I can do it, but I recognize most people aren’t. In addition, people with the intelligence to potentially do it may not want to for fear of bricking their phone, losing official support (which they will), invalidating warranties, etc.
You can root an Android or an iPhone, but you have to keep that separated, in a geek context. For the majority of users it is not a replacement for automatic, supported updates from the manufacturer or carrier.
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.