Let's examine what is fame, shall we?
If you were there as I was in the early to mid-80's, you couldn't get more famous in the pop music world than these four acts: Michael Jackson, Madonna, Cindy Lauper and Culture Club. Between November 1982 when Jackson's album Thriller was released until the album by USA for Africa which featured 36 other singers back in 1985, these four specifically were at the absolute top of pop music fame...
But 1986 was the turning point year for all of them, a make it or break it. Cindy Lauper's album that year yielded only one hit song (True Colours) and a couple of years later starred in a terrible movie flop. One further so-so hit in 1989 and Lauper effectively disappeared from the world's radar, reappearing once in a while for nostalgia fans...
Boy George and Culture Club had it rougher and earlier. On top of the world in November 1984 with Do they know it's Christmas, he spent 1985 hooked on heroin and split up his band, never to re-invent himself and almost vanished entirely, save for the odd hit like the theme song from the movie Crying Game...
The other two singers, do I really have to discuss them? Madonna knows full well how to play the fame game, even today when she is close to being a grandmother, she plays it better than girls a third her age. She never stays too many years without releasing an album, tours the world over, changes her style and adapts to trends, is not at all adverse to using sex and scandal to keep herself relevant (french-kissing Britney and Christina, for one, her SEX coffee-table book for another).
Michael Jackson, despite being a total freak in his personal life, was never a one-trick poney whether it was musical styles or dance steps... Far from following trends, he started many of them!
So here we are, four musical acts who back in late 1985 were arguably at the same level of world fame. Two of these despite visible talent faltered, made choices or for whatever reason today are only remembered by those of age then.
Doubtful these two acts could generate concert sales with tickets at 300$ a seat minimum, like the other two do (or would have, if Jackson were still alive).
But Jackson and Madonna knew how to play the fame game, kept producing a body of work and re-invented themselves to thrive, while so many of their contemporaries are today largely forgotten...
This is why I just scratch my head at many of the comments people put forth in this thread. Celine is totally headed towards the same oblivion as Boy George and Lauper. Plus, her songs have a coolness factor of about minus5, total box office poison to the youth market...