I want to respond to the original poster, I haven't read all the responses in between but much of it seems to have gone off-topic and follows the typical ACF stereotype of Eastern European models being exploited by unscrupulous studio bosses (one studio model just sent me a picture of her new BMW M3, I suppose her studio boss must have a private jet considering he/she takes almost everything the model earns). As well as the group thought that only other cam girls are worthy enough to provide advice to other models.
But that aside, comparing MFC and CB is akin comparing to apples and oranges. CB has a aggressive marketing campaign and offers gay, couple and trans categories. But more importantly, they offer true HD cam feeds and that is something that new customers not only prefer but expect. As I have said before, MFC is still in the age of dial-up with choppy 480p feeds.
MFC has an aging demo of regulars and models and that doesn't bode well for the site's future. You may notice that models who cross cam on both CB and MFC don't even bother to monitor their MFC room, they are solely focused on CB because that's where the money is.
There has always been a decline in earnings during the summer months and that may be what the models on CB are experiencing. As the graph you provided shows, there is a long term decline in traffic (and earnings) on MFC and I don't suspect that will change any time soon, if ever.