When Tom Bosley made the comment, my first thought was Erin Moran. But the more I think about this, the more I think that it might have been Marion Ross. Because I'm guessing that both Erin and Scott Baio received a significant pay raise when they spun-off during Season 10, and they probably received more or less the same when they returned for the final year. But I can imagine Ross, having been there since the VERY beginning, watching others get elevated above her and earning spin-offs and whatnot and deciding to get as much money as she possibly could from the producers. After all, by Season 9 she and Tom were the linchpins of the series (especially after the departure of Ron Howard) and she might have decided that she was indispensable. Given Tom's tone, she discovered otherwise very quickly.
But you can't blame a person for trying.