Are singers not "real artists" if they don't write their own music or play an instrument?

Many famous singers don't play any instruments or write their own music.

Some honourable mentions:

Mariah Carey, Christina Aguilera, Beyonce, Kanye West, Elvis Presley, Rihanna and Celine Dion

Are singers not "real artists" if they don't write their own music or play an instrument?
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