Melvin is slipping quickly in placings, and his physique isn't too far behind. Dexter still looks good, but I think he's starting to show a few signs of slippage too. The judges are probably getting sick and tired of seeing Dexter bring in what looks to be the same package.
And remember, both of these guys have been competing 10yrs. That's a long time, even if you're a top BBer. Most guys are around for 3-4yrs and then they're gone. Even some top level guys are around for just that long, but sometimes their bodies can't take it, so they split. Sometimes I'm amazed that guys like Dex, Melvin and whoever else would stick around for as long as they do. I'd be asking myself "Why?! What's the benefit?"