You are over-emphasizing the influence of the Church on secular society. This is no longer the Medieval Age when Church and State were in very close union, and morals could be better controlled by this union. Today, the Church is seen as a personal means of reaching to God. It is based on our society's view of individualism, relativism and "tolerance". These ideas stretch the limits of what is considered objectively good and objectively evil. This pluralism is not caused by the Church, nor can the Church itself do much besides speak out against secular society.
Things are much worse than in the days of early Christianity. Back then, religion was considered a natural extension of one's daily life. Whether they were pagan or not, religion and morality was taught in schools as part of culture. Now, the Courts have determined, beyond the dictates of the Constitution, to do away with this ancient freedom. Even if the "Church" (according to your definition) comes to said agreements, do you really think that people will turn away from homosexuality, abortion, and the like?
The only way to turn our society around is to evangelize it and convert it. The Church must continue to speak out against evil, but it is only when we bring people into the Church will they then find out how much having God as an active part of their lives enhances it and gives it purpose. Then, the voice of the people will be heard (at least that is how our government is SUPPOSED to work!)
Regards
Today Churches mirror secular society and few see this as a problem. We have the same rate of divorce, people living together out of matrimony, and abortion. It won't be long before we have the same level of unrepentant homosexuals attending. We go to church and hear the things we want to hear, not the things that makes us squirm in our seats. No talk of hell. No talk of repentance. No talk of how we fall far short of God.
The Church no longer speak up about these things. Oh, to be sure there are Church writings on various topics, but how many times have you heard a discussion on divorce, promiscuity or keeping oneself unstained from the world? Sadly most "Christians" today laugh at such "old fashioned" notions or ignore them. And how likely are we to kick someone out of the congregation for practicing such things? Priests and pastors no longer talk about these things for fear of offending.
So the focus is on how much God loves you, have a waffer, drop some money in the collection plate and see you next week. Forget about telling anyone to clean up their act. It's too "preachy". We don't want to hear it.
"The prophets prophesy falsely, and the priests rule on their own authority; and My people love it so! But what will you do at the end of it?" Jer 5:31