Interesting question and answer to this super "Why" is something we can at max opine about. We all are sensing this elephant from various angles, so being judgmental is the last thing to do!
In the unmanifested state, there is no maya which means the soul
was already in pure state.
Soul is in its pure state even with MAyA.
There is another theory, which describes this "unmanifested" to be complete "Nothingness". Which means nothing really exists, yet this "Nothingness" is still identifiable & real!
Paradoxically, this "unmanifested" is beyond what we call "manifested" as well as "unmanifested". Isn't it confusing? That's why I used term "Nothingness" to segregate the former and latter "unmanifested"s:
BG 8.20 — But there is another
eternal (unmanifest) reality, which is beyond this manifested and unmanifested matter. It is supreme and is never
annihilated. When all matter is annihilated, that remains
Adi ShakarachArya's version, provides us 2 inputs:
- The Brahman has an "unmanifested" nature which is eternal (forever)
- The "manifested" nature is also a reality (because "unmanifested" is
referred as "another reality"), but it's not eternal
This shows that irrespective of MAyA is present or not, the eternal reality (Advaita calls it "soul") remains in its pure state.
So why did God decide to manifest himself, why he created different
universes?
Before this "Why", there could be a big troubling question: "How" this unmanifested nature creates the 1st ever "anything" with no resources? I don't have a clue about this "Everything out of Nothing" magic. But since, it's not asked, let's duck that question and assume it to be "the way it is".
Let's call "God" as the manifested reality. So your question boils down to: "Why does God manifests anything at all?" The answer is:
"Because this is the Dharma of the God.".
At first glance, you may find the answer to be over-simplistic street-smart skip. Hence let me put it in interesting ways:
- "Because manifesting self doesn't serve any Purpose."
- "Because this is the only way, the God doesn't have to answer any
'WHY'".
All the above "Because"s are answering the same thing even though they look contradicting. The reason is that often we link Dharma with "Morality", by conveniently forgetting that "Morality" is not a monopoly, but changes from person to person. Ofcourse, Dharma is not Religion. In shortest form, Dharma is "Being oneself without further expectation". Dharma changes according to entity, hence there is term: Swa-Dharma.
Acting with Swa-Dharma is the only way to disallow the Karma to bind us. The fruits would be generated, but there won't be any attachment. e.g. A thief acts according to Dharma when [s]he neither repents upon punishment nor becomes happy upon escaping.
"Why God acts according to Swa-Dharma?", for the same reason: Detachment. Because God is neutral, Karma of creating universes, manifesting self etc. doesn't bind. There is no reason to create/destroy, it just creates/destroys due to own nature. God is just vibrating the way it should:
BG 9.8, 9.9 — The whole cosmic
order is under Me. Under My will it is automatically manifested again
and again and annihilated at the end.
— O Dhanañjaya, all these work cannot bind Me. I am ever detached
from all these material activities, seated as though neutral.
If God didn't create everything, then there was no need for souls
to realize the truth
There is indeed never a need for Jivas to realize self. The things must be fine without it.
Moksha is lack of "purpose", "need", "goal". As soon as we relate Moksha with anyone of these destinations, it slides away like a mirage in dessert. Think of life as wet hands and Moksha as a wet soap on your palm. It's quite handy, but the moment you try to grab it, it slips away.
Moksha or self-realization is a state which is "received", Not "achieved".
Such opinion is from MA ShArada, RAmAnujAchArya, MAdhavAchArya, ...
(various articles and wikipedia, where they term it as Krupa)
BG 3.18 — He (A self-realized
man) has no purpose to fulfill in the discharge of his prescribed
duties, nor has he any reason not to perform such work. Nor has he any
need to depend on any other living being.
Footnote
If you believe above interpretations and are disappointed then there is a reason to be happy! Moksha is equivalent to assuming God's own nature, which is granted to all the entities at the end of Kalpa. But not to be too excited either. According to Ramana Maharshi, the actual nature is "thought-less-ness". If we "think" that after achieving Moksha we will enjoy some bliss, then there are chances of disappointment. Because that "bliss" might turnout to be "nothingness".