The whole point of the Sanhedrin is that for 2000 years there has been no central Jewish religious authority on spiritual matters. This rebbe and that rebbe, and this interpretation and that, and more and more confusion...... and all the while no illusion of any national existence. Just fractionated communities. And more and more sheeplike behavior and defenselessness in the face of angry hoardes of antisemites (the curse of the galut).
JudeanonCapta's audio files in the Torah section explain some of this well - Rav Bar Chayim's shiur entitled "the breakdown of the halachic system." Being a rabbi requires courage. There will need to be enough immensely scholarly and righteous (middos included) chachamim with enough courage to reconstitute the Sanhedrin. At that point legally binding decisions can be made about how to apply the Torah law on the national level. Ie - how to run an army, an electrical grid, etc etc. All the modern concerns that must be approached within the framework of Jewish law and the scholarly interpretation of what the Torah permits and what it forbids. No more saying everyone is correct and valid and no decision can be made either way because I can't disagree with this one and can't disagree with that one and we can't be a nation until moschiach and G-d does it all for us. No more of that.
It's not about what an everyday Shlomo has in his possession or in his house or what he can do. It's about establishing the parameters to renew Jewish national existence in a faith based framework. And the Sanhedrin doesn't elect mouthpiece puppets like the shiite fanatics (again, I don't dignify this with a comparison to the nazi Iranian Muslim mullahs, but you keep insisting). The Sanhedrin is a balance of power with the executive branch, whether it's "nasi," king, set of judges, or what have you.