I think the story demonstrates that the producers need to take on the idea that the show is for amateurs to make their name. Yes its great when they do actually find someone that was an amateur, but they need to realise that they can't artificially create a Subo or Paul Potts moment with any accuracy. Why isn't it reasonable to create a superstar out of jobbing musicians? BGT has never stated that it is for amateurs only, but has allowed the perception to be accepted. It could do the Johnson Brothers and other acts more harm than good by not acknowledging what they actually do.
It will do no good to the so called dream makers if people in the real world outside Digital Spy become as cynical as the people within it, and it will be to those act's detriment in the long run. TV companies can just create another format.