Conversation so far:
When did Larry Bird retire?
Following his Olympic experience, on August 18, 1992, Bird announced his retirement as an NBA player.
What was his plan for post retirement?
In 1989, Bird published his autobiography, Drive: The Story of My Life with Bob Ryan.
The book chronicles his life and career up to the 1989 NBA season.
Did he promote his book?
CANNOTANSWER.
What other activities did he get into post-retirement career-wise?
The Celtics employed Bird as a special assistant in the team's front office from 1992 until 1997.

Question: Why did it only last until 1997?
Self-contained rewrite: Why did Larry Bird's employment with the Celtics as a special assistant in the team's front office only last until 1997?