"Crashed" and "messed up" maybe some but "bricked?" Haven't seen that on XDA. Rarely ever is there a "brick" that can't be "unbricked" in minutes with the right tools (and the right forum). If your forum-folk has had soooo many issues it leads me to believe they aren't too, ummmm, knowledgeable. I haven't had a crashed device since my first Android back in the beginning. Maybe because I don't run odd-ball apps. I don't even remember the last FC I have gotten. Again, maybe due to the apps I use. All pretty safe. I root them within minutes of taking them out of the package.
I don't dispute what you're saying...but I can tell you that many, many folks who attempted or executed rooting had a wide range of problems, and some bricking as well. To your point, it's not for either the faint-hearted nor uninformed. XDA loyalists tend to be some advanced users, so they likely have far better results.
My Android tablet has never crashed either.
As for Jelly Bean...based on the accelerated release of new hardware...I suspect it will be a dominant Android version within months of its release on each device that can run it.