When Oliver left RKO in 1935 to sign with Metro-Goldwyn-Mayer, RKO attempted to continue the series with Helen Broderick and then ZaSu Pitts, but Oliver's presence was sorely missed and the films were poorly received.
The passage highlights that Oliver's departure from RKO led to difficulties continuing the film series. The lack of his presence and subsequent attempts by RKO to replace him resulted in poorly received movies.