It looks like his best days are behind him.
He looked very bad at the Tour this year. Way out of position in the sprint finishes and he couldn't get through the mountains either. Not good. He's also a sprinter that needs the perfect leadout to deliver him almost to the line. He can't, and never really could, do it on his own like Sagan can.
I'm not sure what kind of guy Mercks was, but Cav is a whining little sheet at times and is generally a pretty unlikable fellow, so I'm not sorry he won't break Eddies record.