Who exactly has finished Ben Henderson or Aldo, or BJ at lightweight? Yeah exactly. No one is finishing him either.
This is a prime example of why (outside of BJ) nobody cares about anything below WW.
But anyway, Edgar plays everything smart. He loses to Bendo, so complains for a rematch. Loses to Bendo again, knows there's a big payday out there and nobody cares about FW, so he gets a title shot there. He lost that, so he's trying to pick a fight with the next best guy to fight available. And he knows if he wins that, even though he'd be 1-3 in his last 4 UFC fights, he would probably get another title shot.