In the 60`s, my dad used to say to me, about any bands that I liked, (including those that you mention), "Lets see where they are in 5 years time". Sadly for him, his judgement was flawed because they, or their music are still very much around. Who would have thought that The Rolling Stones, for example, would still be selling out large venues after more than 40 years? Will the same happen to N-Dubz and the like?? I may be wrong, but I know what my guess is.