I think Bishop Tobim is correct: people leave because of weak faith. But he doesn't ask the logical follow up question: whose fault is that? He seems to imply that it's the fault of those leaving, and that there is nothing the church can or need do about it. That's wrong.

He does make a few good points. I'm pretty progressive, but I don't think that if the church just becomes more liberal on certain issues, folks will come flocking back to the pews. As he points out, liberal protestant churches are in massive decline also. Conversely I don't think becoming hyper-reactionary or conservative will bring them back in either. 

We live in a secular age. Many young people I know are either actively atheist, or don't see the need for organized religion. They didn't even have a chance to be scarred by various church scandals. Sure, the scandals hurt, deeply, but there's more to it than that.

I don't know what the answer is.  More active witness, and presence could help.