Vedic astrologers have used it for thousands of years and so has traditional astrology, but was the double rulership scheme
in Astrology always so, and/or will it remain so?
Traditional astrology since at least Ptolemy knew of only seven planets or heavenly bodies - the luminaries(Sun and Moon).
and the 5 wandering stars or planets(Mercury, Venus, Mars, Jupiter, and Saturn). The Ascendant and Midheaven were also known but
they were considered spheres or planes and not planets.
The Sun and Moon ruled one sign each, Leo and Cancer respectively, whereas the other five ruled two signs each: Mercury, closest
to the Sun and Moon ruled the adjacent signs of Gemini and Virgo, Venus the next closest ruled the next two signs of Taurus and Libra,
Mars the third from the luminaries ruled Aries and Scorpio, Jupiter further out ruled Sagittarius and Pisces, and Saturn the outermost
from the Sun and Moon ruled Capricorn and Aquarius. The diagram below clarifies this.
The Sun and Moon ruled one sign each, Leo and Cancer respectively, whereas the other five ruled two signs each: Mercury, closest to the Sun and Moon ruled the adjacent signs of Gemini and Virgo, Venus the next closest ruled the next two signs of Taurus and Libra, Mars the third from the luminaries ruled Aries and Scorpio, Jupiter further out ruled Sagittarius and Pisces, and Saturn the outermost from the Sun and Moon ruled Capricorn and Aquarius. The diagram below clarifies this.
Why the Sun and Moon only one sign each and the others two? It's very likely that in primordial Polarean and Hyperborean times, when humans were still etheric and fully bisexual, The Sun and Moon were one body. This body split in mid Lemurian times when the body became both fully physical and sexual, and is reflected in the Adam and Eve saga with Adam being the solar masculine half and Eve being the lunar feminine half. From mid-Lemuria throughout Atlantis and Arya little changed except for select individuals whose double DNA strands were further divided.
Humanity has been purposely kept on this only one double strand system(Sun and Moon) for far too long. The other five strands should have divided as well long ago, but the energies required to unfold them were purposely and selfishly repressed by the powers that be so that they could exercise greater control over us.
Then, in the mid-late 1700's AD something unexpected happened: the planet Uranus was discovered and its energies released. This was when colonialism was in full swing and the stranglehold of Saturn(the Old World) was broken and the New World(Americas) was explored. This opened up one more strand of DNA in humanity and was followed by the discovery of Neptune in 1846 opening up another strand -that of mystical(Neptune) versus religious(Jupiter). Theosophy and the secret societies(Neptune) united to overthrow the stranglehold of the Church(Jupiter).
Finally, in 1930, Pluto was revealed, the other half of the Mars strand. The two previous World Wars was that separation process and we may need a third to complete it, so that Mars will no longer kill and war and instead will divert its energies towards more positive and progressive venues such as discovery and invention. Pluto is the true destroyer or eliminator as well as the regenerator and has the underworld as its home or kingdom.
Pluto's extreme and amoral ways will be counteracted by the next planet(Eris?) which will separate the Venus strand and which we are currently experiencing. Taurus will develop its true full separate nature as will Libra. The final planet(Vulcan?) will separate the Mercury rulership(Gemini/Virgo) after which humanity will finally be complete.
The unfolding of the planet rulership scheme can be better understood in the following diagram based on TIME or orbital perod rather than much of the info given by modern astronomy which is becoming increasingly exposed as fraudulent.