I can only elaborate on what others have said. Compare the Episcopal Church losing a third of its membership in the past forty years; the ACNA has existed for three years and already has over 100,000 members, mostly former disunited Anglican congregations but many, many new members, including myself and several members of my own church. And churches keep being planted.
Typically when I read about the activities of the local Episcopal churches, there’s a superficial admiration of “tradition” (like wearing albs and stoles, and lifting the host), with a mostly pluralistic anything-goes attitude regarding faith. I’ve heard and read Episcopalians brag about how their priest doesn’t believe in the Resurrection or that the Bible is the Word of God, that Jesus was just a nice guy and whether or not he’s the Son, or even if there is a Son, is irrelevant.
In fact in the liberal churches I see this tendency towards being apologetic for calling oneself “Christian”. They encourage imams, swamis, bhikkus, etc. to preach their sermons, specifically present themselves as especially welcoming of “a variety of different views” - which is why you’ll find atheists like Spong in their ranks. They owe it to other religious to be so accepting as to promote them, while increasingly denying orthodox Christian doctrine as somehow offensive.
In such an “open” environment, there aren’t any answers, just hints and suggestions. They can’t offer any more spiritual guidance than “do whatever feels best”. And like many posters have already said, that makes the church redundant. Would you go to a college in which the students merely attended whatever classes they liked best, didn’t have to do homework if they didn’t want, and were taught “E=mc^2…or whatever feels right to you. Formulate your own idea of what E equals.” They would be so accepting of you that you wouldn’t be changed at all by attending. So why get up early on a Sunday morning to sit through a boring feel-good service when you could just go on the way you could? What’s the point?