In the new version, Spencer played a hospital administrator and amateur sleuth.
Deadline noted that reboots of iconic television series are especially difficult to get going, citing an unsuccessful pass at a modern-day Rockford Files starring Steve Carrell.
Lansbury, who never gave her blessing to the reboot, told BBC News that she was "terribly pleased and relieved" that it wouldn't make it to air.
"I knew it was a terrible mistake," she said. "I didn't want to sully the memory."
"Octavia Spencer is a superb actress. She had no business being put into a situation that she couldn't win," the 88-year-old Brit added.