I don't think that the authors condone what Mary becomes. But Mary is like the type of person who can cogently tell you what's wrong with you, even though she can't help herself. Don't you know people like that? I do.
She's an embarrassment in the party scene, but she is also telling the truth about Frank to Frank's face, when there's absolutely nothing left of their friendship and her love and admiration for him. She's like Tiresias at that point. Just one scene further in, and there's still that glimmer of the old Mary as she fights for Frank and Charley's collaboration in "Like It Was".
Charley is the one of the three friends who remains true to his ambitions, even if it means the end of his friendship with Frank. (Clearly, Frank is resentful when the success of Charley's play is mentioned in the first scene, so it does tap into Frank's fear of what he has become).
I think the point of the show is that we leave school, maybe come to New York or some other big city with dreams and aspirations that we betray all along the way, or we don't, if we're very lucky. The trick is staying in touch with that 22-year-old dreamer inside of us. ("Better look back...," as they sing in the opening number). The hope is that at 35-45-55, we don't hate or regret what we've done with our lives. ("One trip. All we get is one quick ride.") That may not be a new or profound thought, but Merrily makes a potent case for it.
I took a friend of mine to see the show in Washington. He doesn't particularly like or get musicals, and had no familiarity with Merrily going in to it. About 20 minutes after leaving the show, while we were walking and discussing it, he said it reminded him of when he first came to New York 16 years ago with a lot of hope for what would happen to him, and two friends of his in particular, who are no longer in his life. Like in some sort of residual shock, he just started to bawl because the show had affected him so deeply, even though he was trying to resist succumbing to his feelings.
As far as the score, I don't really agree with MusicMan's assessment. The title song is melodic and catchy and hooks you right away - though I've never seen it well staged. The horror of the first scene is disturbing, but galvanizing, and "That Frank," though not a terrific song, conveys a lot of information. I think most people can relate to the bittersweet sentiment of "Like It Was," and then "Franklin Shepard Inc." is usually a showstopper. Then, Act One continues with "Old Friends," "Growing Up," "Not a Day Goes By," and "Now You Know," all of which are strong songs, I feel.
Again, as I've admitted, I can't be objective about this show. But I think a lot of people are too hard on its flaws, in view of the things that are very, very right.
"Gif me the cobra jool!"