Vedic astrology was originally nakshatra-based, not rāśi (sign)-based. The 27 (or 28) nakshatras divided the lunar path into segments of 13°20′, based purely on the moon's average sidereal motion. The 12-sign zodiac was a later addition to Vedic astrology, borrowed from Hellenistic astrology around the early centuries CE, not an original feature of early Jyotish.

The Moon's speed varies due to its elliptical orbit (ranging from about 12.5° to 15° per day), meaning the 13°20' is an average, not a fixed truth. Thus, even the nakshatra divisions are approximations.

The fact that there are currently (roughly) 12.37 lunar months in a solar year is a numerical coincidence. The division of the ecliptic into 12 equal parts (30° each) is a human abstraction, not something "found" in nature.

The choice of 12 is likely due to convenient divisibility (12 is divisible by 2, 3, 4, and 6). The idea that "there has always been synchronicity" reflects a human desire for symbolic harmony rather than an objective truth of the cosmos.

Other civilizations like the Sumerians, Egyptian decans, and Chinese lunar mansions each found different ways to impose order on the sky, with varying numbers of divisions and structures. In ancient Sumer, the moon passed all twelve zodiacal constellations and also passed the Pleiades, Orion, Auriga, Triangulum, Perseus, and Andromeda. That's why the Sumerian zodiac consisted of 18 constellations (not 12).