Consider what Motown did in little more than a decade;

Diana Ross & the Supremes, Smokey Robinson & the Miracles, Stevie Wonder, the Temptations, the Four Tops, Marvin Gaye, Michael Jackson & the Jackson 5, Martha Reeves and the Vandellas, Gladys Knight & the Pips, Lionel Richie & the Commodores .. and most of the above had multiple hit albums for Motown.
Even if 'Alicia Keys and Mariah Carey' never consciously learned from the above artists, their trainers sure did.

Also, Motown artists were trained to handle success. This part really perked my ears when I learned it. I think it might be a really important part of developing talent.

I do not work here, but the benefits are still awesome
Make your sound your own!