Wasn't Donahue starting to head toward the "trashy" or "controversial" route by 1988? Just five days after the Geraldo fight was taped, the Election Day 1988 (Nov. 8, 1988) episode of Donahue featured the Gorgeous Ladies of Wrestling:
https://www.youtube.com/watch?v=lTZaVZPzV0s
Then another 1988 episode spot from WDTN-2 Dayton (where Phil's show first was taped from 1967-74 and channel 2 was still airing it in syndication) promoted secrets at bachelor parties:
https://www.youtube.com/watch?v=jkaUosTrzqw
Also from '88--part 1 of the "Love Ritual" episode:
https://www.youtube.com/watch?v=L8nqIm-oJ6s
IMO not entirely '70s/early-to-mid '80s Donahue material. But not quite to the level to being a forerunner of Springer, Maury and the ilk as the show approached its end in the early/mid 90s.