The problem here is that there are multiple reasons for bedwetting, with the Dr.'s advice on immature bladder being only one...if immature bladder is the reason, then her advice is sound...however, if there is another reason (and there are several out there) then different methods may work, like the bed wetting alarm. Her point, I believe, was to list all of the options and why some may or may not work. I myself, am the mother of three, two of which have only had the occasional bed wetting dream/episode...but my third child still wears a pull up to bed at 6 year old...
I believe that the biggest point to make is that in MOST cases it is not through any fault of the child that it happens and thus they should NOT be punished for it. Just keep trying different things until either it stops on it's own or something works...Good Luck...