Reading the Parasha every week, it seems the bulk of the Torah, at least the Written Torah is composed of commandments we don’t practice anymore, and a guide to observance of Judaism in a society that no longer exists (Ancient Israel). So my question is, if we’re not observing the bulk of the mitzvot already, how can we call the Mitzvot we do observe “strict obligations” And why do we observe them in the first place? Should we try and recreate the society the Torah seems to be planning out (with kings, and irei miklat etc.)?
Your observation, that many of the mitzvos unfortunately are not applicable nowadays that we don’t have the Bais Hamikdash is true, however this does not mean that we should just leave the rest. If you walk into a kosher restaurant and you see that most of the menu consists of foods that you can’t eat, does that mean you shouldn’t order something anything? It is true that the optimum society that G-d wants, is when we have the Bais Hamikdash, and all of the Jews are in Eretz Yisroel, but right now that the Jews are in exile, doesn’t mean that the whole religion doesn’t exist. We pray three times a day, and hope that the time of the redemption will come soon, and we will get back to the society that we once had.
Jewish theology teaches that the relationship between G-d and the Jews is similar to a marriage. For example, this is the theme of the Song of Songs, a song of a husband and wife that are separated, and long for the time when they will reunite. When a couple find themselves in a situation that they cannot live together, (i.e. they are in two different countries), does that mean that they are no longer married? No. They still are, and they still fulfill their marital obligations as best as they can. The husband still support’s his wife, and she still takes care of the home, and the children, and they wait for the time that they will get back together again.
Aside from this, the Jews received the Torah on Mount Sinai, even though they weren’t in the holy land, had no king and no Bais Hamikdash. G-d still gave the Jews the commandments, so that they can keep whatever would be applicable for them at that time.
Additionally, although the optimum Jewish society is with a king etc., the Jewish religion is not based on a Jewish society, rather on a personal relationship with G-d. This is something that we have been doing although we have been in exile for about 2000 years.
Regarding your other question if we should try to recreate the society that the torah has planned out. There are certain things that we can help, and those we should try to do. This includes building as strong of a religious community as we can, with Jewish school etc., so we can live a Jewish life as best as we can. However, rebuilding the Bais Hamikdash, and reinstating its service are beyond our capabilities at this point. Right now we are all ritually impure, and also because we have to wait for the messiah to reinstate the kingdom of David, and rebuild the Temple. See Maimonides (Melachim Chap. 11)