That is absolutely right. Not only ban of signature campaigns negatively affect this forum but on the other hand, if signature campaigns lower pay rate as low as 40-50 USD per week, then this forum will experience significant lose of high quality posters and will be left with bunch of spammers. By the way, I wonder why other forums didn't copy this strategy of Bitcointalk, i.e. to allow signature campaigns. I don't wanna be "that" guy but I think that o_e_l_e_o was here because of high pay rate and he left because of low pay rate and we lost a very amazing member because of that! o_e_l_e_o was a real asset (I know he said that he had an illness but I don't believe it, sorry but I love him, he will always be in my memory).
Let's be honest we can't know 100% if o_e_l_e_o really left the forum because of his health issues or for some other reason. We can only make educated guesses based on his post history and since he looks like a genuine a person, I'd say the chances for him telling the truth are higher than 90%. Is it 100%? Unless you know him in real life and saw his hospital records, you can't tell that and I think nobody here knows him in real life.
But saying that he left the forum because he didn't get paid enough is a serious accusation.
Leave the forum and do what? There isn't any other forum where you can make that much money just by posting anywhere on the internet.
So I think what you say is very unlikely.
I think if he had good health, he would be around and making posts even if there were no sig camps available. That's the impression I got from him.