your case is described simply as "being stuck on boot". being bricked is a different matter.
yes it happens all the time, try to search the forum for "stuck on boot" just to get an idea of how often this happens.
just flash the stock, flash the rooted kernel, and this time, try one of the apps on play store that have the option to update the Su binary. maybe the update mechanism you tried is old or something, i don't know why this happened to you.