It was safe for Pike to return to Talos IV because neither he nor Vina were in condition as breeders. Spock realized it was a "logical" solution to Pike's retirement problem because the Talosians could "free" him from his physical body.
FORBIDDEN PLANET was unquestionably an influence on STAR TREK. Just that scene with Adams and Quinn about how impossible it is to fix the broken gear screams "Kirk & Scotty!" ("I need warp speed in three minutes, or we're all dead.") The stories of the Krell and of the Talosians are very similar, but the movie writers put a lid on it by destroying Altair IV.
But there's no putting genies back in bottles. During the development of atomic weapons, some Manhattan Project scientists urged politicians to not use the device because exploding it would "give away" the secret that such a weapon was even possible. Since other scientists elsewhere in the world were already working on the problem, burying the American research (which was also being funneled to the Soviet Union by spies) would have made no difference. Someone would eventually rediscover the work.
After reading the
FORBIDDEN PLANET novelization and a
prequel story (which was not all that good), I realized that Altaira could have been the focus of a sequel. I don't see such sequel as a marketable movie, but a novel might explore some interesting concepts. You see, Alta must have been exposed to the "plastic educator" because she was joined to Morbius during the attack of the "id monster"—she
saw the whole thing as a nightmare. So, how much of the Krell knowledge had she absorbed? Morbius must have known he wouldn't live long enough to complete his researches, and so needed an heir. Aside from the usual protectiveness of a father for his daughter, the arrival of the C-57D threatened his whole project just like the
Beleraphon did.
The books prompted some other realizations. In the movie we see Earth fauna, which Morbius explains away as specimens from a Krell expedition to Earth millions of years ago. To the best of our knowledge, deer and tigers then did not look like their modern variants. Nor is it likely that they'd look like modern Earth types after such a long separation on Altair IV. Then Adams has to kill a tiger that tries to attack him. My first impression on seeing the film is that it was because Morbius made the tiger attack. Now I realize that the tiger, as such, did not really exist. When the great cataclysm destroyed the Krell—
and everything on the surface of the planet—any specimens from Earth would have been destroyed along with everything else. But since Morbius had read about Earth specimens in the Krell records, he expected to see some—and the great machine provided. Morbius even tells us how the power gauges on the machine register when birds migrate. In other words, the tiger was yet another "id monster" similar to the one that attacked the C-57D.
And there's more.
Morbius tells Adams that the
Beleraphon skipper was killed by his exposure to the plastic educator. Was that another subconscious attack by Morbius, or was the skipper's brain just too different to take the "brain boost" the way Morbius did? (And later Altaira.) Consider: the Krell had visited Earth. Is it possible they "tinkered" with some of the animals there, like Arthur C. Clarke's extraterrestrials in 2001: A SPACE ODYSSEY? That is, did Morbius survive the plastic educator because he was a descendant of a hominid that had been modified by the Krell? Morbius even jokes about it, "A commander doesn't need a high IQ, just a loud voice."
A sequel to that story could be most fascinating. The Talosians? Not so much. They're just the ultimate couch potatoes. (But I'll check out the books mentioned above.)
