I don't see a link to the page, but highly doubt that there is a valid conclusion that treatment for a year provides assurance of no relapse.
Relapses are very common, and there have been trials of abx that document relapses or flares, even after a year of prophylactic doses. I hope this comment doesn't depress you further, but if so there is still hope. Our child improved dramatically with puberty - though not all do. I have found that the job becomes chasing all the triggers (including non-strep), as we don't seem to have a cure for the immune dysfunction, except possibly puberty.