I saw a TV interview with Thusrston Howell III, Jim Backus was actually a good friend of Sherwood Schwartz.
Despite that, he thought the show was sort of dumb. There were all kinds of social messages supposedly but Backus never understood any of them.
The only thing which made it a success was the cast which was actually pretty good. Also I think everyone likes to imagine what it would be like shipwrecked on a desert isle which had all the things needed for survival.
Also I kept imagining what I would do with Mary Ann.
Nothing deeper than that.
Even though our modern eyes may interpret things differently.
BTW, Mary Ann was the hot one!