That's what the recent issue of Pharma Marketing News (link to pdf download) explores. While it doesn't come up with a whole lot of new answers—I think we're all waiting for the latest ACCME data report—it does have this to say:
Well, let's wait and see. From what I hear, some CME providers are doing better than ever with commercial support, while others are struggling, so I guess your perception of how the market is doing really is what counts. Still, I'll be curious to see what shakes out in the ACCME data.