Conversation so far:
What is significant during the Rowan & Martin's Laugh-In season 4?
The 1970–71 Rowan & Martin's Laugh-In brought new additions to the cast include sad-eyed Dennis Allen, comic actress Ann Elder, tap dancer Barbara Sharma, and Johnny Brown.
What else happened in Rowan & Martin's Laugh-In season 4 besides new additions to the cast including sad-eyed Dennis Allen, comic actress Ann Elder, tap dancer Barbara Sharma, and Johnny Brown?
Arte Johnson, who created many memorable characters, insisted on star billing. The producer mollified him, but had announcer Gary Owens read Johnson's credit as a separate sentence.
Is there anything significant about Arte Johnson insisting on star billing but was credited in a separate sentence?
This maneuver gave Johnson star billing, but made it sound like he was still part of the ensemble cast. Johnson left the show after the 1970–71 season.

Question: Did anyone else leave?
Self-contained rewrite: Did anyone leave Rowan & Martin's Laugh-In besides Arte Johnson during seasons 4 and 5?