Final answer:
Walter Cronkite was the TV ratings pioneer who died in 1980 and was a significant figure in American television journalism, hosting the CBS Nightly News and influencing public opinion on the Vietnam War.
Step-by-step explanation:
The TV ratings pioneer who passed away at 82 in 1980 was Walter Cronkite. Walter Cronkite was renowned for his role as the chief commentator and host of CBS Nightly News and was often referred to as "the most trusted man in America." His influential voice in journalism was highlighted when he publicly criticized the Johnson administration on its handling of the Vietnam War, which was a significant moment leading up to President Lyndon Johnson’s announcement not to run for another term.
Cronkite’s career was during a time when television broadcasting was considered risky due to the requirement for live broadcasts, but his contributions were part of the expanding impact of television on American culture including the rise of television journalism through news shows like CBS' See It Now and the coverage of major political events such as the 1960 elections, which marked the beginning of "the age of television" in American politics.