Why are accurate premonitions so rare? Is their rarity wholly a result of extraterrestrial manipulation of human capabilities?

Both of these things are true. Premonitions would be quite routine and daily events if people were in the state of functioning originally designed for the human being. As a divine human, you have an intuitive reach that has been tampered with by extraterrestrial manipulation. This was done very soon after the beginning of life on Earth when the human colony was discovered by the Anunnaki visiting the solar system from their own star system and they immediately decided to commandeer humans for use as slaves and altered their DNA to dim down the intuitive reach. This is like taking away all of the antennas needed for communications of radio signals and other transmissions of information so people have only a meager ability to sense things compared to their normal capability. This is most unfortunate because it makes people extremely vulnerable because they do not have their normal wits about them as a consequence. It is very much akin to being blind. It is a sixth sense we are speaking of here, the intuitive reach, and it is normally quite profound and quite useful because it brings in whole bodies of information at once and provides knowing in a deep sense about many, many things of interest. It is an inexhaustible storehouse of knowledge one can tap into intuitively if the capability is there and unhindered. Unfortunately, humans have a severe impairment and will get bits and pieces, and some will be quite impeded and have no perception of any kind of higher awareness, and then a very few will have seemingly amazing psychic ability but that is still relative to the original uncorrupted state which is still far greater.