Not even the Professor can provide a believable explanation for this reincarnation of "Gilligan's Island." I was one of those people who never tried to make sense of the original live-action series (I realized it was an inside joke). This time, however, even I have to break down and ask the Professor the infamous question, "How can you build a spaceship but you can't fix a..." Okay, okay, I know we all know the end of THAT punch line.
I'm not sure, but I think the only reason so few episodes were made was because Filmation went out of business. Filmation also did those "new age Popeye" cartoons with what I'll call "PSAs" to kids about health and safety. Otherwise, there may have been another 2-3 year run of "Gilligan's Planet."
Nevertheless, I'm willing to admit that I found it entertaining as a kid simply from its sheer ridiculousness. Why not? I found "Rubik, the Amazing Cube" quite mesmerizing, too!