Our Gemara on amud aleph seems to indicate that Kiddush with wine is part of the Deoraysa (Biblical) mitzvah of declaring Shabbos, and not merely a rabbinic requirement.  Therefore, it may be that one would not be able to fulfill the Biblical obligation of Kiddush Friday night without wine (although this is subject to debate, compare the mefaresh “Harey Mushba”, 4b with Tosafos. Also see Rabbenu Tam, Sefer Hayashar 62.)

If we are going to consider wine to be such an essential ingredient, we must come to understand what is the ultimate purpose of this endeavor.  Obviously, we can all agree that the celebratory aspects of the feasting and wine allow for consecration and sacralization of Shabbos.  But, it is more than that. We find that Yitschok used the feast of delicacies and wine to arouse himself into a meditative prophetic state to bless his son (Bereishis 27:25). How does this work? Is this just about getting high?

Yes and no.  Getting high is a human experience, and it doesn’t only come from alcohol or even a drug. Music also can induce a prophetic state (see Rashi Tehillim 23:1)  It is not easy to silence the distractions of physicality in order to perceive the spiritual realm.  We are constantly organizing reality, but also limiting it through our forced perceptions and defenses. The Gemara (Eruvin 65a) states:

אָמַר רַבִּי חָנִין: לֹא נִבְרָא יַיִן אֶלָּא לְנַחֵם אֲבֵלִים וּלְשַׁלֵּם שָׂכָר לָרְשָׁעִים, שֶׁנֶּאֱמַר: ״תְּנוּ שֵׁכָר לְאוֹבֵד וְגוֹ׳״.

Rabbi Ḥanin said: Wine was created only in order to comfort mourners in their distress, and to reward the wicked in this world so they will have no reward left in the World-to-Come, as it is stated: “Give strong drink to him that is ready to perish, and wine to the bitter of soul. Let him drink, and forget his poverty, and remember his misery no more” (Proverbs 31:6). “Him that is ready to perish” refers to the wicked, who will perish from the world, while “the bitter of soul” denotes mourners.

Rav Tzaddok (Pri Tzaddik Lech Lecha 3) explains this allegorically.  WE, who have lost paradise and were expelled from the Garden of Eden, are the mourners who need to be comforted.  Wine can be used to bring us back to that Edenic state, or if abused, can lead us to the fate of the wicked. 

The Rambam in Guide (III:51) almost poetically describes the manner in which physical and spiritual are at odds, and how one cannot serve two masters simultaneously:

I have shown you that the intellect which emanates from God unto us is the link that joins us to God. You have it in your power to strengthen that bond, if you choose to do so, or to weaken it gradually, till it breaks if you prefer this. It will only become strong when you employ it in the love of God, and seek that love: it will be weakened when you direct your thoughts to other things. You must know that even if you were the wisest man in respect to the true knowledge of God, you break the bond between you and God whenever you turn entirely your thoughts to the necessary food or any necessary business; you are then not with God, and He is not with you: for that relation between you and Him is actually interrupted in those moments. The pious were therefore particular to restrict the time in which they could not meditate upon the name of God, and cautioned others about it

Ironically, opposites are true. The Nazir’s abstention from wine represents a way to separate from physical lusts and distractions in order to train the body and soul toward higher sensitivities.  Yet, the use of alcohol also is a method of slightly loosening the hold of the physical world so that we can experience the sublime.  As with most theological and ethical issues, the key is to have the right balance.  Mesilas Yesharim (26) discusses that after a person strives for attachment to Hashem and limiting physical lusts, he can by divine gift, reach a supernatural engagement transcending the physical.  Yet, even in that state, he says:

והנה האיש המתקדש בקדושת בוראו אפילו מעשיו הגשמיים חוזרים להיות ענייני קדושה ממש, וסימניך אכילת קדשים שהיא עצמה מצות עשה, ואמרו ז"ל (פסחים נט ב): כהנים אוכלים ובעלים מתכפרים.

Behold, for the man sanctified with the holiness of his Creator, even his physical deeds become actual matters of holiness. A sign of this is in "the eating of temple offerings", which our sages of blessed memory said: "the priests eat and the owners obtain atonement" (Pesachim 59b).