Shar,
To begin, I don't think the bishops are at all serious about getting those who have left to come back.  The signs of this are overly abundant, but at the end of the day, I'm left with the sense that many of these guys breath a sigh of relief and utter "good riddance."  I can't say I've EVER gotten the sense of one following the parables of Jesus regarding lost sheep or treasures.  Those who leave (or lose faith) are simply not seen as "treasures."

As to the average pew sitter, what you say may be true, though I suspect there may be more awareness than you think.  Some of those folks monitor, but stay anyway, choosing the easier path. Leaving can be very difficult if one takes his/her spiritual life seriously.