Mark said:
Booth was ill at the time and the last season had a nurse on set with her all the time. CBS offered to renew it for another year but Booth bowed out saying she was too ill, though she didn't die till 1992.
People sometimes don't realize that all the money in the world (and Shirley Booth probably made peanuts compared to series stars today, though 25 grand a week wouldn't be out of the question...great money any era...) cannot preserve your health.