Firing Line with William F. Buckley Jr., broadcast 1966-1999, was exclusively on PBS only from 1971, so 28 years.
Burns, a Democrat and Democrat donor, was 18 in 1971 and can't have been very well acquainted with the long-standing opinion already existing at the time among conservatives that PBS was hostile to conservatism.
As it was, neither The McLaughlin Group nor Firing Line ever received favorable time slots on PBS.
In point of fact, in Chicago back in the day Saturday night at our house was always make-pizzas-at-home-night, when most people went out. We wanted to stay home to enjoy watching both of these programs, which were broadcast back to back during the dinner hour on PBS, often followed by The Three Stooges and Svengoolie on a different channel, WCIU 26.
The playing field for conservatism was never level at PBS, and certainly isn't now.