I dIdnt necessarily say he was finished, but when he fought Jackson , they were talking up the fact that he would be better served dropping down to LMW. He was getting battered and then came the KO punch. Before the fight , it was seen as a name in Jackson's young undefeated career. Then all of a sudden he gets offered Korobov out of the blue and suddenly he's a born again MW.
Again, he was getting outboxed and he caught Korobov and to be fair , finished him well.
The Quillin fight meant nothing
a. Because he knew he couldn't lose his title. And
b. Because the fact that Quillin couldn't make the weight after being out for so long, meant that he was either rusty or unprepared.