I believe the point is not that the zodiacs don’t occur at all, it’s that the time you are born is no longer the same time the original zodiac occured.

The fact humans are able to track them is how we know the zodiacs are no longer accurate. According to astrology if you were born on Dec. 1 for example, you’re considered a Sagittarius… except you’re ACTUALLY a Scorpio, due to the constellations shifting.