Are you getting reeled in after each attack? If so, the other riders are recognizing you and don't want to join you because you aren't successful. When you're already pushing at 99%, it's not worth the extra strain unless you are pretty sure that group can stay out front. I knew a guy who made an attack almost every lap of a crit (on the back straight because he did some eratic moves that would get his license thrown out), we'd reel him in but nobody ever tried to join a break with him, because he couldn't hold it for more than a thousand feet.