One of the criticisms levelled at “The Call of Cthulhu” is that Cthulhu isn’t the immense threat that fans claim: after all, he was defeated in 1925 by someone driving a boat into his head so would be no match for modern weapons. However, while it is certainly true The Alert ended his pursuit by ramming him, focusing on that misses a greater threat: his magic, faith, hyperscience, or whatever one chooses to call it.
Cthulhu isn’t a god; Lovecraft calls him “the great priest“. Whatever threat he poses in himself, he is also a worshipper of beings vastly greater than him; beings that other Lovecraft stories show both have inconceivable power that is either magic or a functionally equivalent hyperscience and respond to prayers and invocations. So, saying The Alert‘s collision shows Cthulhu isn’t much of a threat is equivalent to saying the Catholic Church couldn’t vastly affect society because it’s easy to knock a vicar over with a truck.
And even considering only Cthulhu’s personal power, the collision isn’t a death blow or even a serious injury, but rather an inconvenience; Johansen’s narrative states that he visibly heals in the time it takes The Alert to move out of sight. No one would say an intercontinental nuclear missile isn’t a threat because one could smash it with a hammer. How much more of a threat might one consider that missile if it could rebuild itself within a short period of having been smashed?
Some might argue—not utterly without basis—that the collision was more than inconvenience; that Cthulhu and R’yleh sank again, so he must have been significantly weakened. However, that is not what Lovecraft says: the narrator says that Cthulhu “must have been trapped by the sinking whilst within his black abyss, or else the world would by now be screaming with fright and frenzy“. The strongest proof of Cthulhu’s weakness is only a lack of primary evidence to the contrary.
Lovecraft does however give us secondary evidence that Cthulhu didn’t sink. Johansen suffered a rather suggestive nightmare after escaping R’lyeh:
“There is a sense of spectral whirling through liquid gulfs of infinity, of dizzying rides through reeling universes on a comet’s tail, and of hysterical plunges from the pit to the moon and from the moon back again to the pit, all livened by a cachinnating chorus of the distorted, hilarious elder gods and the green, bat-winged mocking imps of Tartarus.”
“The Call of Cthulhu” starts with the awakening of Cthulhu causing artists and other sensitive individuals to suffer strange dreams. So, it is almost certain this nightmare is an echo of Cthulhu’s waking actions after the collision. Actions that are not a collapse into a coma due to injuries, but flight across universes (plural). Cthulhu’s power after this supposed defeat by The Alert was great enough he could still move between universes.
Perhaps that final plunge to the pit was a return to R’yleh—but if so it was due to the whimsy of those elder gods and not insignificant human technology.
Or perhaps the world is not screaming with fright and frenzy because Cthulhu awoke and chose to depart Earth without significant interaction, in the same way a human might return home to see an ant’s nest on their lawn and simply walk by.