Why dont tyra banks sing?

She's sang a few songs but none of them took off...

Personally I never thought she was any good, she's average at best when it comes to singing so she sticks to what she knows.

From her wiki page
"Music
Banks has appeared in several music videos, including Michael Jackson's "Black or White", Tina Turner's "Love Thing", Mobb Deep's "Trife Life", George Michael's "Too Funky" (with fellow supermodel Linda Evangelista) and Lionel Richie's "Don't Wanna Lose You". In 2004, she recorded her first single, "Shake Ya Body," which had a music video featuring the final six contestants on America's Next Top Model, Cycle 2. The video was world-premiered on UPN, but the single turned out to be a failure.[18]
Banks released a single with NBA player Kobe Bryant, entitled "K.O.B.E.," which was performed on NBA TV.[citation needed] She also has a single on the soundtrack to Disney Channel's Original Movie Life-Size called "Be A Star."[citation needed]"