Well look at Usher. His voice is still high. But then again, look what happened to Lil Bow Wow. But then again again, Lil Bow Wow raps, not sings, and unlike singing, hip hop popularity is a phase, just like rock n roll, disco, jazz, blues,...etc was. Unfortunately for Lil Bow Wow, the hip hop generation (who are now the parents) kind of ended in late 2008. So, unless Bow Wow collaborates with someone who is still managing to shine through in the hip hop arena, or puts out something that is so hot that it's undeniable, he's pretty much done if he can't just sing. I'm sure he could do well on a house track or two.
Anyway, I wonder is Justin Bieber can outlast the predictions of his critics? What if he becomes the male version of Britney or Madonna, who just happens to keep going and going? The real question is how long will Lady Gaga last? Yes, she's had a bunch of successful hits, but do notice how many she's had in such a short space of time, and how many different sounds she's already covered. How long will Lady Gaga last at the fast pace rate she's going? Britney at least spaces out her stuff. I believe Madonna also spaced out the time of her releases as well. Lastly, keep in mind that Michael Jackson was able to manage getting through puberty.. and didn't all members of New Edition do the same?