Why did Hendrick Motorsports let Kyle Busch go?

Answer 1

Roush Fenway Racing and Matt Kenseth never specified why contract talks abruptly broke down in 2012.

Going into that season, the team had plans on a long-term contract to have Kenseth retire at Roush Fenway.

Answer 2

Kurt Busch never drove for Hendrick Motorsports. That was his brother Kyle. He is gone basically because the folks at Hendrick Motorsports chose not to babysit a childish driver.

Answer 3

Because Hendrick wanted to make room for Dale Jr.